Wild card Adam Walton was proud of his fight after pulling off the biggest shock of the French Open so far as he beat Daniil Medvedev in five sets, rallying late on to get the victory.

It is the seventh time – and the second year in a row – that Medvedev has been knocked out at the first hurdle at Roland-Garros.

It was a rollercoaster of a match, though Walton completed a stunning turnaround in the deciding set to clinch a 6-2 1-6 6-1 1-6 6-4 victory in a marathon three-hour-and-23-minute tussle in the searing heat in Paris.

Medvedev held off two break points in the opening game, but Walton still took the first set with a four-game winning streak, though he could not keep up his momentum.

The contest ebbed and flowed, with the Russian pulling back into the match with a strong second set, only to drop the third by the same 6-1 scoreline.

Medvedev, who got into an argument with his wife mid-match after complaining about the temperatures on Court Suzanne-Lenglen, again fought his way back in during the fourth and looked set to cruise over the finish line after going 4-2 up.

But Walton, who earned his first win against a top-10 opponent, did not panic and put together another four-game winning stretch to get over the line and book his place in the second round.

"I'm pretty tired right now," Walton said in his on-court interview. "It was such an up-and-down match.

"I got off to a hot start, and I felt like the ebbs and flows of the match were quite large. I'm just really proud of my efforts in the fifth set, to come from a break down to get the win.

"I thought, with the game at 1-3, I faced some break points there, and if I go down 1-4 with a double break, it's going to be pretty tough from there.

"So, getting that hold and keeping the score close, I knew if I just kept fighting, maybe I would get a chance. I'm glad I did."

Walton will now face Zachary Svajda, who beat Alexei Popyrin 3-6 6-3 7-6 (7-3) 7-5.

There was also a slice of history at Roland-Garros on Tuesday, as 17-year-old Moise Kouame became the first man born in 2008 or later to win a grand slam match.

He overcame former world number three Marin Cilic 7-6 (7-4) 6-2 6-1 in front of his home crowd with an ice-cool performance.

Kouame is the youngest player in the Open Era to defeat a grand slam champion in the men's singles at Roland-Garros, surpassing Michael Chang en route to the title in 1989 (Ivan Lendl in the round of 16 and Stefan Edberg in the final).