Live Commentary: Agnieszka Radwanska vs. Li Na - as it happened

Afternoon everybody! It's ladies' quarter-final day at the All England Club and the last eight is a truly surprising one.

Yes, seven of the eight remaining are seeded but only three of those are in the top 10 seeds. Two of those are in action first up on Centre in Radwanska and Li.

The only unseeded player left in the draw is Estonia's Kaia Kanepi, who ended teenage Brit Laura Robson's run at the Championships yesterday.

Kanepi is up against 23rd seed Sabine Lisicki. Already a favourite at SW19, the German won over even more fans yesterday by knocking out number one seed and defending champion Serena Williams. Those two are first up over on No. 1 Court.

We'll have commentary on that Lisicki-Kanepi match live on site shortly. When it's there, I'll provide the link.

The only former champion left in the draw is eighth seed Petra Kvitova, who defeated Maria Sharapova in the 2011 final. The Czech is up against surprise package Kirsten Flipkens, seeded 20th, who is yet to lose a set at this year's Championships. They're on Centre after this Radwanska-Li match.

The final match is between up-and-coming American Sloane Stephens and experienced Frenchwoman Marion Bartoli. They'll be second on No. 1 Court.

WEATHER WATCH! We had sunshine aplenty at the All England Club yesterday but it's much more overcast today. The latest forecast tells us that the rain should stay away until later this evening, hopefully allowing all four quarter-finals to be completed.

I have to say that my favourite to progress today is Radwanska. She is seeded slightly higher at four, compared to Li's six, but that's not the only reason. The 24-year-old Pole reached the final here last year but was defeated by Serena Williams 6-1 5-7 6-2. Taking a set off Serena in the final was a good achievement and I expect her to handle the Centre Court pressure better today.

However, Li Na has won a Grand Slam. She claimed the 2011 French Open to become Asia's first-ever singles champion at Slam level. It's tough to call but I'm siding with Aggy.

The players are chatting and smiling backstage before just after the clock strikes 1pm they are instructed out onto court. Centre is pretty empty at the moment but it's sure to fill up as the match nears its beginning.

H2H: These two have met plenty of times and it's Li who leads 6-4. Their last meeting was at the Australian Open in January where the Chinese beat Radwanska in the quarter-finals, ending the Pole's 13-match winning streak at the time.

Despite her record, I'm still backing Aggy this afternoon. Li is slight favourite with the bookies, however.

Chair umpire Lucy Grant announces that Li won the toss and chose to receive.

Warm-ups done, the two players stride out from their chairs. Here we go...

Awesome start from Li as she latches onto Radwanska's serve and bullets a return winner down the line.

And now THREE BREAK POINTS for Li at 0-40 as she finds another forehand winner.

BREAK! Goodness me, what a start by the Chinese. She wins the first four points against serve to immediately break.

The sixth seed's opening service game doesn't begin well though as she nudges a backhand volley wide.

It's now Radwanska who moves to 0-40 on her opponent's serve and she has BREAK POINTS too...

BREAK! Hmmmm. The Pole also breaks to love and that's one of the oddest starts you'll see to a tennis match. Expect many more breaks today as neither woman is particularly confident on serve but much better at returning.

Radwanska wins the first point on serve to make it 15-15.

We have a hold! Radwanska improves greatly towards the end of that game, even putting away a confident drop volley at the net to seal the game.

Best rally of the match so far. Li approaches the net and Radwanska forces her into a tough volley that the Chinese can only pop up. Radwanska doesn't put it away though and allows Li to lob her but the point isn't done as Radwanska loops the ball high into the air and it drops just inside the line. Li blasts the smash straight Radwanska but she can't get it back in play.

After those nightmare service games to start, both women have now held serve. Li does so with a big up-the-line backhand at advantage.

Superb from Radwanska! She offers up Li a short ball but guesses that the Chinese will go back behind her and manages to hit a winner up the line with Li well out of position.

She's a clever one, is Radwanska. She closes out the game by drawing Li into the net and swiping away the volley that is presented to her.

There's a moment of confusion as the line judge has to correct himself so Radwanska decides to challenge his call. Li's shot was in though and umpire Grant says that it's 40-15. Radwanska isn't happy though as she didn't stop the point, the line judge did and so the decision is changed to replay the point.

Li goes on to hold to 30 and we remain level in the opening set. Over on No. 1, Lisicki remains a break up against Kanepi serving at 3-2.

Since those two breaks-to-love to begin the match, neither woman has offered up a break point. Radwanska is able to hold to 30 as Li misses with three straight returns.

Li has now made seven unforced errors to Radwanska's four. The Chinese does go for more winners though and I would expect her unforced-error count to be higher come the end of the match.

A lovely forehand pass from Radwanska followed by a mishit approach from Li sees the Pole move ahead at 15-30. Nervous moments for the Chinese but she responds with her first ACE.

It's BREAK POINT Radwanska though as Li's forehand barely makes it halfway up the net...

Once the rally had begun there I was expecting Li to make an error but it's Aggy who hits long with her back and we're at deuce.

A second break point of the game for Aggy but it's saved again by Li thanks to a big first serve.

Dear, dear me. Radwanska spoons up the easiest of smashes for Li on game point but the sixth seed mishits it long. Shocker!

Poor decision from the umpire there. Li found the edge of the baseline but it was called out late. She challenges and HawkEye shows that it was in. Radwanska had hit her shot into the net and because it was a late call the point should be given to Li but umpire Grant says "replay the point."

The Chinese recovers well from that though to hold serve with a pair of winners, her 12th and 13th of the match.

Over on No. 1, Lisicki takes the first set 6-3 against Kanepi with a second break of serve. Follow the second with Sian Cowper here.

Back to Centre and Li has TWO BREAK POINTS as Radwanska's lob drifts long...

The Pole saves the first with a cheeky drop shot followed by a backhand down the line that Li can't get a decent racket on.

A first serve down the T is then returned out by Li and we're back to deuce.

BREAK! The sixth seed is given another chance to break and this time she takes it with a beautiful forehand up the line. She'll now serve for the opener.

Two monster rallies to begin, one won by either woman. Both have to take a little breather as Li tries hold her serve nerve to take the set.

SET POINT LI...

Brilliantly saved by Radwanska! Li comes to the net but Radwanska has the beating of her with a low pass and then backhand winner with Li somewhat stranded at the net.

Another set point is saved by the Pole. Li is all over the point but Radwanska stays in it before the Chinese hits wide with a forehand.

Stunning defence from Radwanska to save another set point! Li hits a fine forehand that the Pole can only spoon up for a smash but it's hit straight back to her and she finds a backhand winner down the line. Back to deuce.

Another set point saved! That's four now.

Radwanska reads the serve and blocks it over the highest part of the net and she now has a BREAK POINT...

BREAK BACK! Unbelievable defence again from the Pole before Li hits wide with a backhand. The elder of the two women will be devastated there as she squandered FOUR set points.

Over on No. 1 Court, Kanepi broke Lisicki to go ahead in the second but the German broke straight back and is now leading 3-2 on serve in the second set.

Radwanska with her first double fault but it's the best time to do it at 40-0.

The double is followed by a careless volley but she manages to hold as Li misses a simple forehand of her own at the net.

This is interesting... Li banged down a first serve in the previous game at set point which BBC Sport's HawkEye system shows was in. Had she challenged that at the time then we'd be playing the second set right now.

UPDATE: Lisicki has turned the second set on its head over on No. 1, winning four games on the bounces to move 5-2 ahead. She's one game from a place in the semi-finals.

Into a tie-break we go as Li holds to 15. I'm backing Radwanska here...

Radwanska 0-1* Li. Instant mini-break for the Chinese.

Radwanska 1-1* Li. Radwanska levels it up straight away.

Radwanska *1-2 Li

Radwanska *1-3 Li. Another mini-break for Li.

Radwanska 2-3* Li

Radwanska 3-3* Li. The players change ends back level on serve as Li hits wide with a backhand.

On No. 1, Lisicki is about to serve for the match...

Radwanska *3-4 Li

We've now had exactly an hour of play on Centre.

Radwanska *3-5 Li. Another mini-break to Li thanks to some big hitting off both wings.

Radwanska 4-5* Li. The Chinese will have two service points for the set.

Radwanska 5-5* Li. She squanders the mini-break for a third time.

Radwanska *6-5 Li. SET POINT Radwanska!

SET! Call the police, there's been a robbery on Centre Court!

Li had four set points earlier in the set and actually won one of them but didn't challenge a bad call off her serve. In the tie-break it was Li who moved ahead on three occasions but kept relinquishing the mini-break before Radwanska made her pay.

RAIN AT WIMBLEDON! Just as the first set comes to an end, the heavens open and the match is interrupted. The covers are on quickly and I reckon the organisers might choose not to put the roof on because this shower should be brief.

With all the drama of that tie-break, I couldn't bring you news of Lisicki's victory over on No. 1. She saw off Kanepi 6-3 6-3 and will face the winner of this match on Thursday in the last four. The German sweetheart is definitely now favourite for the tournament.

Just as expected, the covers are being taken off already as that really was a short downpour.

Radwanska and Li are back out on court and we'll be back underway shortly with Li to open the serving in the second set.

That break in play will have allowed Li some time to mull over that first set. She'll be wondering quite how she lost it but will now need to regain her focus.

A love hold to start the second for Li. The perfect way to get over the opening set.

Radwanska also holds, recovering from 0-30 and winning four straight points. She seals the game with a serve down the T that took a bit of a dodgy bounce off the centre line.

Radwanska is ahead in the game at 15-30 but Li doesn't buckle under plenty of deep pressure from the Pole and we're back level at 30-30.

She dumps a forehand into the net on the next though and it's BREAK POINT Radwanska...

Saved by Li as her net cord pops up for Radwanska but her approach is so tame and Li has an easy job passing the fourth seed.

BREAK! Radwanska has another chance to break and this time she does, drawing Li forward with a slice and the Chinese can't whip it over.

A real change in momentum in this set as Li won the first six points of it but is now a break down.

Li looks good to break straight back at 0-30 but two return errors from the sixth seed and we're back to 30-30.

That's a second hold in this set from 0-30 for Radwanska and it's not the Pole's good play that's doing it, more Li's inconsistency.

UPDATE: Over on No. 1, the next quarter-final between Sloane Stephens and Marion Bartoli is about to start. I'd open this commentary by Liam Power in a new tab if I were you.

Li's now in serious trouble on serve. She hasn't offered Radwanska a break point but isn't converting her game points. We're at deuce.

The Chinese manages to hold at the third attempt though with an assured forehand volley.

Radwanska moves to within two games of the match by holding to 30. Li is running out of chances to take this into a decider.

Li stays in touch with a hold to 15, finishing the game off with a rare serve-and-volley.

Strange start to the next game as Li is offered a simple drive-volley but she plays it straight back to the Pole, who had given up the point. Radwanska doesn't even both moving her feet and just swats the ball lazily back past her opponent crosscourt for a winner.

BREAK-BACK POINT for Li as she she does well to hit a tough overhead into the open court...

BREAK BACK! She's got it, again dominating Radwanska from the baseline. Aggy loves throwing up a high ball to challenge her opponent but again Li is confident enough to drive-volley the ball out of the air for a winner and we're back on serve in the second.

Li with an extremely fortunate hold of serve that included three dead net cords. Radwanska also had one chance to earn the break straight back but couldn't take it.

BREAK AND SET! Li moves to 0-30, as she did twice earlier on in the second set, but this time is able to convert the advantage and grab the set. We're headed to a decider on Centre!

Radwanska isn't happy and calls for the trainer to address a problem, seemingly with her right quadricep. Or thigh to most of us.

Umpire Grant announces that Radwanska is now receiving a three-minute medical timeout. Li puts a jacket on to keep her warm and takes out some notes to over her third-set plans.

Radwanska is OK to continue and it will be Li to open the serving in the decider.

BREAK! That five-minute seeing to by the trainer seems to have rejuvenated Radwanska as she moves to 0-40 before converting her second break point with an up-the-line winner.

Radwanska plonks a forehand right in the corner to bring it back to 30-30 but then is lobbed by Li after another fortunate net cord for the Chinese. It's break-back point but saved by Radwanska.

Superb way to hold for the Pole. She bends low to angle an in-to-out forehand near the line. Li sprints across and gets it back but Radwanska is at the net and puts away the volley.

RAIN! It's falling again on Centre Court. Li begins her service game but surely they'll be stopping soon?

We're not stopping yet as the brollies continue to be opened on Centre. Li moves to 40-15 with a pair of backhand winners but then DOUBLE FAULTS TWICE and we're at deuce.

PLAY IS SUSPENDED! Li hits a drive-volley to move to advantage but then the ground staff sprint out and put the covers on.

Over on No. 1, they've also stopped and it's a crucial time to do so. Stephens is serving 4-5 down and it's deuce on her serve.

THE ROOF IS CLOSING! The tournament directors decide that this rain might not be going away and decide to close the roof. It will be around 20 minutes until the players return to court and we're also going to have a little break. The commentary will go back live at about 4pm. See you shortly.

We're back!

The roof is closed and Radwanska and Li are back out on court and warming up their serve. Remember, Radwanska is a break up in final set at 2-0 and Li is serving at advantage with a point to get on the board. Resumption imminent...

The pair are back in their chairs after one point as Radwanska nets a forehand.

Radwanska remains a break ahead in the decider as she holds to 15.

Big, big trouble now for Li Na at 0-30 on her own serve.

Radwanska is disgusted with herself as she spoons up an easy smash for Li after a poor volley by the sixth seed.

Radwanska has two chances to open up a double-break lead but can't take either. Li hanging on!

Another break point goes begging for Radwanska but now she has a fourth opportunity...

The Pole slips over mid-rally and can't get back up in time to make decent contact with the ball.

DOUBLE BREAK! At the fifth time of asking Radwanska earns the double break as Li hits wide with a forehand. She challenges the call but it was an inch out and is that game, set and match?

A rare unreturnable serve from Radwanska at 40-30 sees her hold serve and she's now one game away from a place in the last four.

It's 30-40 and MATCH POINT Radwanska...

Well saved by Li! She plans a down-the-line backhand right into the corner before putting away a drive-volley into the open court.

Li follows that up with a double fault and it's a second match point...

Saved again with an excellent low forehand volley. That's the 66th time she's come to the net. Unheard of for the Chinese.

Li comes through that service game, forcing Radwanska to serve it out.

Oddly, Radwanska calls for the trainer again despite the fact that she has three more games to close this match out.

Just a quick massage of the left thigh this time for the Pole and she's already back out serving.

Li has two break-back points at 40-15 but they're BOTH SAVED by Radwanska, first with a stunning backhand winner basically sitting down before Li shoots wide with a backhand of her own.

A third match point for Radwanska...

Dear me, a double fault!

Match point number five is saved by Li as she comes to net and her volley drops ONTO THE LINE. Incredible scenes on Centre.

And now the Chinese has a point to get one break back...

Fantastic response from Radwanska as she hits a forehand to the corner and puts away the drive-volley.

ANOTHER match point goes begging. Back to deuce again.

And another! This is getting silly.

That's seven match points that have been saved now as Li again finds a superb return.

The fourth seed gets it done at last at the eighth time of asking!

She will now face the German on a charge, Sabine Lisicki, in the last four at SW19.

A strange game that took two hours and 46 minutes of playing time but was interrupted twice by rain. It wasn't the best in terms of quality but intriguing all the same.

Next up is the only former champion left in the women's draw - Petra Kvitova. She takes on Belgium's Kirsten Flipkens, enjoying an excellent run at this year's Championships. The commentary for that one will be live on site shortly. See you there.