Jannik Sinner, Carlos Alcaraz survive scares in Madrid

Top-seeded Jannik Sinner of Italy and No. 2 seed Carlos Alcaraz of Spain each dropped a set in their respective matches on Tuesday, while rebounding to advance into the quarterfinals of the Madrid Open.

No. 4 seed Alexander Zverev of Germany and fifth-seeded Casper Ruud of Norway both lost in straight sets.

Sinner reached the quarterfinals at Madrid for the first time, rebounding from dropping the first set to defeat No. 16 seed Karen Khachanov of Russia 5-7, 6-3, 6-3.

With the first set tied 5-5, Khachanov broke Sinner's serve en route to a 7-5 set victory. Sinner returned the favor in the second set while leading 1-0, then broke Khachanov twice in the third to put the match away.

"I think today was really tough, because at some points he served really well, so it was tough to return," Sinner said. "I made a couple of mistakes in the first set when he broke me, but this can happen. In the second set I tried to stay focused immediately, I broke him, and the confidence level raised a bit."

Facing No. 23 seed Jan Lennard-Struff of Germany, Alcaraz survived 6-3, 6-7 (5), 7-6 (4) in a rematch of last year's final, also won by Alcaraz in three sets.

In a nearly three-hour match that saw the momentum swing both ways at different stages, Alcaraz captured the final four points and secured the win on his fifth match point.

"This match reminded me a lot of last year's," Alcaraz said on court after the match. "It was pretty difficult from the first point until the last one. It was a great fight. It was difficult for me to deal with my emotions, to handle certain moments in the match. ... I kept fighting, and that's all that matters so I'm really happy to get the win at the end."

Alcaraz will next face seventh-seeded Andrey Rublev of Russia, who has yet to drop a set in the tournament. Rublev disposed of No. 24 seed Tallon Griekspoor of the Netherlands 6-2, 6-4.

No. 3 seed Daniil Medvedev of Russia advanced to the quarters with a 7-6 (3), 6-4 win over No. 17 seed Alexander Bublik of Kazakhstan. Medvedev will face the winner of the Rafael Nadal-Jiri Lehecka match scheduled for later Tuesday.

Zverev fell 6-3, 6-4 to No. 21 seed Francisco Cerundolo of Argentina, who won 79 percent of his first-serve points and saved both break points. He also broke Zverev twice and posted 19 winners to Zverev's nine.

Cerundolo's next opponent is 12th-seeded American Taylor Fritz, who upended No. 8 seed Hubert Huracz of Poland 7-6 (2), 6-4.

Ruud, meanwhile, was dispatched 6-4, 7-5 by unseeded Canadian Felix Auger-Aliassime, who will take on Sinner in the quarterfinals.

Auger-Aliassime had three aces to Ruud's six and four double faults while Ruud had none, and also overcame five service breaks. Auger-Aliassime dominated in winners (34-17) and points at the net (24-8).