Abel Hernandez put Hull in front just 31 seconds after the restart, but the Tigers were denied at the death by Welbeck's finish from inside the box.
Here, Sports Mole looks at a dramatic 90 minutes in North London.
On target: 9
On target: 4
Was the result fair?
The stats above suggest that Arsenal should have cruised to victory in this match, but that would be misleading. The Gunners did control possession and put the Hull defence under heavy pressure for long periods, but the Tigers held out admirably and were worthy of their hard-earned point today.
The first half was almost one-way traffic as the Gunners searched for a way through, with Hull's equalising goal very much coming against the run of play. Indeed, it looked far more likely that Arsenal would extend their lead than see it wiped out, but the hosts found it harder to get in behind Hull after the leveller.
That was the case in the second half too, with substitute goalkeeper Eldin Jakupovic only being forced into action in the dying stages of the match. Even so, the Gunners did deserve something from this one as they created the better chances and controlled the game, so a share of the spoils is about right.
While nine shots on target is a major improvement from the zero that they managed against Chelsea last time out, Arsene Wenger will still be concerned with how little his side threatened in the final third - particularly during the second half. Arsenal were more or less camped on the edge of the Hull box throughout, but still they struggled to find a way through.
Their passing was too sloppy at times as they found it tough to deal with Hull's energetic pressing. They were often forced into efforts from long range - which they had plenty of - but more often than not there was a Hull defender in the way to block it. It is always going to be tough to break down a side that has 10 men behind the ball, but there was a lack of creativity at times from the hosts.
Even so, there are positives for Wenger to take from this match. Aaron Ramsey returned from injury - although Jack Wilshere departed with a knee problem - and his side once again showed the character to come back and rescue a point. However, they have now drawn five of their opening eight games and are already 11 points behind Chelsea, a gap that could prove to be unassailable.
Steve Bruce seemed to be making a brave choice when he went for a 3-5-2 formation this afternoon, but in reality it was more like a 5-4-1. The Tigers spent the vast majority of their time defending and rarely broke forward to put the makeshift Arsenal defence under any real pressure.
Hernandez, in due to an injury to Nikica Jelavic in the warm-up, cut an isolated figure during his time on the field as Hull packed 10 men behind the ball at every available opportunity. Still, the game plan worked for the visitors as they managed to score twice, keeping up their fine recent form in front of goal.
They defended magnificently as well, throwing themselves in the way of everything to keep Arsenal at bay. They were under the cosh a little before Diame's equaliser, but, from that moment on, they were superb at the back. Hull may play better than this and lose this season, but a point at the Emirates is a very good result for the Tigers.
Sports Mole's man of the match
Michael Dawson: It was not a textbook performance from the Hull defence, with players often forced into last-gasp blocks, but Michael Dawson carried them out to perfection. He always seemed to be there to deny an Arsenal man, and his countless blocks made things a lot easier for Jakupovic.
The former Tottenham Hotspur man was unable to finish the match, having gone off with around five minutes left due to an injury, and perhaps, if he had still been on the field, Hull may have claimed all three points. Even so, he can be proud of a heroic performance at the heart of the visiting defence.
This one has to go to referee Roger East. Diame's equaliser should never have stood after he tugged Mathieu Flamini back in the build-up, but the referee allowed it, much to the fury of the Arsenal defenders. It was a clear pull and the hosts should have had a free kick.
It was a tricky match for East today. The above decision was the biggest one for him to make, and he also got a number of smaller calls wrong, which left Wenger exasperated on the touchline at times. Not the official's finest hour.
Arsenal: The Gunners are back on European duty on Wednesday as they head to Belgium to face Anderlecht in the Champions League.
Hull: Hull, meanwhile, face another daunting away trip as they take on Liverpool at Anfield next Saturday.