Defending champion Carlos Alcaraz was forced to fight for his place in the French Open fourth round with a testing victory over a dogged Damir Dzumhur.

The second seed had looked to be making light work of his opponent with a two-set lead, before a revival from the Bosnian pushed their encounter into a fourth set under the lights on Court Philippe Chatrier.

Spaniard Alcaraz, seeking to becoming the first man since compatriot Rafael Nadal in 2020 to retain the Roland Garros title, eventually ground out a 6-1 6-3 4-6 6-4 success.

"I didn't enjoy it too much," said the 22-year-old. "I suffered quite a lot but I'm happy to have played a good match with Damir.

"That's why it's difficult to win Grand Slams because you have to maintain your focus over three or four hours.

"The first two sets were under control and then he decided to play deeper and more aggressive. My energy went down and it was hard to push, but I had to give everything I had inside. I'm proud to get the win in the end."

Alcaraz will face 13th seed Ben Shelton next after the American beat Italy's Matteo Gigante 6-3 6-3 6-4 earlier on Friday.

Alcaraz's form during his second-round win over Fabian Marozsan had been patchy and Friday's first meeting at ATP Tour level against Dzumhur looked set to be a much smoother affair.

Having shrugged off two early break points, he reeled off five successive games to wrap up the opening set inside 30 minutes, with his opponent looking exasperated at times as he struggled to contain the man seen as the one to beat on the Paris clay this year.

The second set followed in much the same fashion, and while Dzumhur, 33, did have his chances with break points in the second and sixth games, he lacked the weapons to cause Alcaraz any concern.

A double fault sealed the two-set lead for the Spaniard, but then the errors started to creep into his own game in the third as Dzumhur found another gear on the other side of the net.

After a brief pause to receive treatment on a knee injury, the Bosnian - seeking to reach the fourth round of a Slam for the first time - finally got the break he had been fighting for.

Alcaraz wasted three immediate chances to break back at 4-3 down, and a further two as his opponent served out the set.

Dzumhur's resurgence continued into the fourth as he broke the frustrated Spaniard at the first time of asking, and Alcaraz was forced to watch more break points of his own come and go unconverted.

But Dzumhur was only ever going to hold him off temporarily.

Alcaraz, starting to show glimpses of the clinical form on show in the opening two sets, won four successive games, and while he was broken back when serving for the match, he again broke Dzumhur to close the tie as the clock neared midnight in the French capital.

Rune to face Musetti next but injured Fils withdraws

Danish 10th seed Holger Rune also reached the fourth round by beating France's Quentin Halys in five sets.

Rune, who stunned Alcaraz in the final to win the Barcelona Open last month, had to come from two-sets-to-one down in a 4-6 6-2 5-7 7-5 6-2 victory.

Rune will next face Italian eighth seed Lorenzo Musetti, who beat Argentine Mariano Navone in four sets.

Elsewhere, 12th seed Tommy Paul won his second five-set match in a row to set up a fourth-round tie with Australian 25th seed Alexei Popyrin.

The American, 28, ousted Russian 24th seed Karen Khachanov 3-6 6-3 7-6 (9-7) 3-6 6-3, while Popyrin recorded a 6-4 7-6 (13-11) 7-6 (7-5) win over Portugal's Nuno Borges.

American 15th seed Frances Tiafoe beat compatriot and 23rd seed Sebastian Korda 7-6 (8-6) 6-3 6-4 and will face unseeded German Daniel Altmaier next.

Altmaier reached the fourth round of a Grand Slam for the first time by defeating Serbia's Hamad Medjedovic 4-6 6-3 6-3 6-2.

French 14th seed Arthur Fils, who overcame injury to beat Jaume Munar on Thursday, has pulled out of Saturday's third-round tie with Russian 17th seed Andrey Rublev.

Rublev will face Italian top seed Jannik Sinner or Czech Jiri Lehecka in the fourth round, with the pair due to meet on Saturday.