World number one Novak Djokovic reached his 26th consecutive Grand Slam quarter-final but only after surviving a US Open scare against Spain's Roberto Bautista Agut.

The 2011 champion won 6-3, 4-6, 6-4, 6-3 to set-up a clash against Spanish veteran Feliciano Lopez in what will also be his ninth US Open last-eight place in a row.

Djokovic gave up a 4-2 lead in the second set and saw an early break clawed back in the fourth by the 23rd seeded Agut, a former junior footballer with Villarreal in Spain.

The Serb was also broken when serving for the match at 5-2 as Agut unleashed a barrage of deep, murderous forehands before steadying himself to claim his 60th win of the year.

"He fought and hung in there. It was a great match," said Djokovic, who hit 42 winners but also committed 37 unforced errors.

"I had a couple of points to break for 5-2 in the second set but I didn't capitalise and the match turned around.

"He made me work for it -- there were no free points."

Lopez, 33, reached his first US Open quarter-final at the 14th attempt with a 6-3, 7-6 (7/5), 6-1 win over Italy's Fabio Fognini, the conqueror of Rafael Nadal in the previous round.

"Lopez is not the typical Spanish player. He comes into the net on first and second serve. He serves and volleys, uses a lot of slice," said Djokovic.

Lopez, the 18th seed, said Djokovic will hold the cards having won all of the pair's five meetings.

The Spanish left-hander has only ever taken one set off Djokovic and that was in their first meeting at the 2007 Australian Open.

"I will be 34 in September so it's a great feeling to be playing like this and reaching my first US Open quarter-final," he said.

- 'No weaknesses' -

"When Novak plays good, you don't know what to do to be honest. He has no weaknesses in his game."

Lopez had put out 10th seed Milos Raonic in the third round after having been just four points away from defeat against Mardy Fish in the second round.

But he was rarely threatened by Fognini, breaking in the fourth game of the first set and then coming back from 3-1 down in the second.

Fognini, the 32nd seed and bidding to become the first Italian to reach the last eight in a decade, required a medical timeout on a back injury at the end of the set.

At 3-0 down in the third, he needed an inhaler to regulate his breathing before he went on to drop serve again in the sixth game.

"I saw the way Fabio was hitting winners past Rafa in the final set and I was scared he was going to do that to me," said Lopez.

Defending champion Marin Cilic and Jo-Wilfried Tsonga set-up Tuesday's other quarter-final clash.

Cilic made the last eight for the fourth time with a 6-3, 2-6, 7-6 (7/2) 6-1 win over France's Jeremy Chardy.

Cilic, the Croatian ninth seed, took his record in New York to 11 successive wins after capturing his maiden Grand Slam title in the city last year.

But the 26-year-old had to overcome an injury scare in the second set to stay alive in the tournament when he rolled his right ankle.

"I twisted my ankle in the second set but I tried not to let it affect my movement," he said.

"In the first few games of the third set, I was conscious of it but after that I didn't have any trouble."

Cilic fired 23 aces and 52 winners in his win.

French 19th seed Tsonga reached his second New York quarter-final with a 6-4, 6-3, 6-4 win over unseeded compatriot Benoit Paire, the man who opened up the draw by knocking out fourth seed Kei Nishikori in the first round.

The 30-year-old Tsonga has now held all 56 service games at the tournament.

Cilic has a 4-1 career lead over Tsonga in main tour matches, winning the pair's last three without dropping a set.

Tsonga's only win was in the 2011 Cincinnati Masters.

"I have the feeling that I am playing my best tennis and I hope this will continue," said Tsonga, who made the quarter-finals four years ago.
Source: AFP