It was not nearly as straight forward for Nadal this time, with the Spaniard looking rusty during the two hours and 31 minutes it took him to eventually see off Pouille 4-6 7-6 (8/6) 7-5.

The Frenchman will wonder how he did not repeat his 2016 US Open victory over Nadal.

He had two match points at 6-4 in the second-set tie-break and engineered a glorious chance to take the first on his own serve only to net a mid-court forehand.

Pouille also looked the stronger player in the decider but again could not take his chances and Nadal survived.

Grigor Dimitrov will face Juan Martin del Potro in an attractive round-two clash after both won on Tuesday.

Third seed Dimitrov defeated in-form Damir Dzumhur 6-1 3-6 6-3 while Del Potro was a 7-6 (7/4) 6-4 winner against Pablo Cuevas.

Nick Kyrgios thumped Nikoloz Basilashvili 6-1 6-2 and there were also wins for John Isner, Tomas Berdych and Andrey Rublev.

Milos Raonic made his comeback from the wrist problem that ruled him out of the US Open with a 6-3 6-4 victory over Viktor Troicki at the Japan Open.

The Canadian has been beset with injuries in 2017, with the latest one keeping him out for nearly two months.

American Steve Johnson claimed the biggest scalp of his career with a 4-6 7-6 (7/5) 6-4 victory over second seed Dominic Thiem but countryman Sam Querrey lost 6-4 7-6 (7/2) to Richard Gasquet.

The defeat deals a potentially serious blow to Querrey's hopes of qualifying for the ATP World Tour Finals for the first time.