Result: Roger Federer reaches final eight

Former world number one Roger Federer moved into the fifth round of the US Open with a straight-sets victory over Juan Monaco.

The last 16 encounter didn't commence until just before midnight local time, but the wait failed to hamper the Swiss player's performance.

Federer dropped just three games in the whole match on his way to a 6-1 6-2 6-0 win on the Arthur Ashe Stadium.

After the encounter, Federer revealed that he felt sympathy towards his Argentinian opponent.

"It's tough for Juan. I've been in that position before when I lost badly on this court to Andre Agassi, so I know what it feels like," said the 30-year-old.

"Sometimes it's just not your day but it was mine tonight and it feels great."

The five-time US Open champion will now face Jo-Wilfried Tsonga in the next round.