Alex de Minaur was not at his best against French veteran Adrian Mannarino as Wimbledon's fourth day opened with the sun out and mercury rising, but he was good enough.

The Australian fifth seed saw off his potentially troublesome left-handed opponent 6-3 6-2 6-2 in one hour 49 minutes on Thursday.

De Minaur won the first two sets in 38 minutes each, breaking twice in the first set and thrice in the second.

His own serve occasionally malfunctioned, and he was broken in each set, with the second delivery especially vulnerable.

In the third, there was no such blemish, though he had to survive a lengthy service game at 2-2, which featured five deuces. 

He followed up to break his downcast opponent.

That was effectively it, with 38-year-old Mannarino never going to come back from two sets and a break down. 

De Minaur held again and broke again, to love.

Solid Aussie support

With Maya Joint, then James Duckworth following him onto court 3 there was solid Aussie support for de Minaur. 

They were rewarded with a better performance than his nervy first-round win over Roman Andres Burruchaga in the same arena.

Getting better as the tournament progresses is the aim of every contender and de Minaur is fulfilling that target so far.

"I definitely think I started better, I had more intent, more conviction in what I needed to do," de Minaur said, adding he was "super stoked and super grateful to be playing some good tennis with some great weather here in London.

"I just love it here and I'm hoping I can stay here for a long time."

De Minaur's third round opponent will be either Kamil Majchrzak, who surprisingly beat him in the final at 's-Hertogenbosch recently, the Pole's first win in three meetings, or American Zach Svajda, who de Minaur has never faced.

AAP