Federer was off the pace from the start, producing a number of poor shots before losing the first set in the tie-break after sending a backhand wide to give Andreev set-point before another wayward effort saw the Russian take the first set.

The Swiss drew level after winning a second-set tie-break and showed the form he is capable of to win the third set 6-3, but Andreev fought back to win the fourth 6-3 and take the game into a final set. Federer then raised his game once again to come through a tough contest that lasted just over three-and-a-half-hours.

Federer's next opponent, Gilles Muller, had earlier progressed after defeating fifth seed Nikolay Davydenko 6-4 4-6 6-3 7-6 (12/10).

Muller, who hails from Luxembourg, fired down an impressive 20 aces to secure his place in the quarter-finals.

Novak Djokovic was made to work hard but responded well to the test provided by Tommy Robredo to book his place in the last eight.

The third seed from Serbia lost the first set to the Spaniard, seeded 15, before battling back to win the fourth-round meeting 4-6 6-2 6-3 5-7 6-3 in an epic contest that lasted three hours and 44 minutes.

While Federer and Djokovic were pushed to the limit, Andy Roddick barely broke a sweat in a 6-2 6-4 6-1 rout of 11th seed Fernando Gonzalez of Chile.

The eighth-seeded Roddick won 53 of 62 points on his serve and faced only one break point against Gonzalez as he attempts to win his second US Open title.