German fifth seed Alexander Zverev came through a frustrating first-round match against world number 56 John Millman after dropping two sets in Paris.

Zverev, 22, won 7-6 (7-4) 6-3 2-6 6-7 (5-7) 6-3 in over four hours but smashed his racquet several times.

He was two sets up before being pegged back by Australian Millman but broke late in the deciding set to seal a win.

Meanwhile, Argentine eighth seed Juan Martin del Potro came through a scare to beat Nicolas Jarry 3-6 6-2 6-1 6-4.

Del Potro, 30, lost the first set to the Chilean world number 58 but recovered to win in just over two hours on Suzanne Lenglen.

The racquet smashing continued

Zverev, who reached the quarter-finals in Roland Garros last year, has struggled for form since stunning world number one Novak Djokovic to win the ATP Finals in November.

He lost to Canadian world number 18 Milos Raonic in the fourth round of the Australian Open.

And his racquet-smashing display on Philippe Chatrier was a familiar sight for fans who had seen Zverev become frustrated in that defeat by Raonic back in January.

A spectacular meltdown while seated at a changeover in Melbourne was not quite replayed in Paris on Tuesday but there were several racquet smashes and roars of frustration in another underwhelming performance.

The German went two sets up but was broken twice in the third and was dominated in a fourth-set tie-break. He also had a break point saved at 3-2 up in the fifth before eventually getting the job done.

Zverev was lucky to avoid the same fate as Roger Federer, who was shocked by Millman in the the fourth round of the US Open.

The 22-year-old will face Swedish qualifier Mikael Ymer in the second round.

Del Potro survives scare

Eighth seed Del Potro will face either Japan's Yoshihito Nishioka or the USA's Mackenzie McDonald in the next round after also coming through a scare in his first-round tie.

The Argentine, who is seeking a first Grand Slam win since becoming US Open champion 10 years ago, went on to dominate after falling a set behind.

Del Potro, who reached the Italian Open quarter-finals this month, broke Jarry's serve five times to seal the win.

He reached the French Open semi-finals last year, where he lost in straight sets to eventual champion Rafael Nadal.