Alexander Zverev saved a match point as he conjured up another fightback to win an epic clash with Damir Dzumhur and reach the fourth round of the French Open for the first time on Friday.

The second seed came from two sets to one down to beat Dusan Lajovic in the second round on Wednesday and had to do the same again two days later to break new ground at Roland Garros.

Dzumhur spurned the chance to serve out the match in the fourth set and had a match point in the decider, but the world number three won a thriller 6-2 3-6 4-6 7-6 (7-3) 7-5 on Court Philippe Chatrier.

Zverev has never reached a grand slam quarter-final and was facing another failure before coming back from the brink of defeat to set up an encounter with Lucas Pouille or Karen Khachanov.

Dzumhur was outstanding for much of a gripping contest which took three hours and 54 minutes to settle, but the 21-year-old Zverev gave another demonstration that he has come of age to deny the 26th seed in what was his first grand-slam victory over a player ranked inside the world's top 50.

Zverev start aggressively, taking a 2-1 lead courtesy of a Dzumhur double fault and mixing up fierce groundstrokes with deft drop shots as he went a double break up and wrapped up the first set with ease.

Dzumhur was up against it when Zverev secured an early break in the second, but the 27-year-old warmed to the task under grey skies and deservedly got back on serve at 3-3.

The Sarajevo-born underdog had the bit between his teeth, one of several dexterous drop shots and a forehand winner down the line putting him a break up at 4-3 - an advantage he pressed home to level it up at one set apiece.

An overcooked Zverev backhand put him 2-1 down in the third and although he got back on serve before coming back to hold from 0-40 down, a stray forehand gave Dzumhur the chance to serve for the set.

The rampant Dzumhur grasped that opportunity and continued to give Zverev the run-around, keeping his focus after colliding with a ball boy - who initially stayed down but was able to walk off court.

Zverev was rattled, making two woeful unforced errors to go 3-2 down in the fourth, but levelled at 4-4 and broke back to love to stay alive when Dzumhur made a mess of serving out the match. 

The towering favourite bossed a tie-break which ended when Dzumhur put a backhand low into the net sliding to his left and took the upper hand in a final set which saw the first three games go against serve.

Dzumhur threw his racket down, but he was not finished yet, exquisite drop shots and his powerful forehand getting him back in it at 4-4.

Zverev saved a match point before making it 5-5 and went on to win the next two games, a stray forehand consigning Dzumhur to a heartbreaking defeat.