Self-proclaimed Wimbledon "underdog" Casper Ruud kept his composure to navigate into the second round on Monday.

The No.4 seed has been open about his struggles on grass courts, but managed to nullify the threat of qualifier Laurent Lokoli 6-1, 5-7, 6-4, 6-3 under the roof on No.1 Court.

The four-set victory sends the Norwegian into a second round clash with British wild card Liam Broady.

"It was great fun," Ruud said. "It was a great first time on Court One, it's a very special court. I've watched many legendary matches on here on TV in my childhood. So to be here myself was a very fun moment for me."

Back in action for the first time since falling to Novak Djokovic in the Roland-Garros final earlier this month, the Norwegian adapted to the grass, finding his footing.

"I take every match as an underdog at Wimbledon," said the world No.4, who came into The Championships with a 1-3 Wimbledon record.

"I haven't got the perfect game to play on grass, but today I think I did quite well. I consider many other players favourite to do well here before myself.

"So, I'm just going to try to play loose, not with too much pressure and just enjoy every time I get to step out on the most beautiful tennis courts in the world."

Ruud quickly clicked into Grand Slam mode.

The 24-year-old sent a backhand pass down the line and delivered a couple of forehand cross court winners to move 5-0 ahead in just 19 minutes.

The No.1 Court crowd gave Wimbledon debutant Lokoli a raucous reception when he finally posted a game, but Ruud was too determined, opening up a set lead.

The world No.199 was far from deterred, cajoling the crowd at every turn to increase his support in the stands.

He attacked with confidence, using plenty of chips and trips to the net, managing to keep step with the Norwegian.

At 5-6 Ruud had his first serious test. A snappy volley from the Frenchman followed by a crunching forehand down the line prompted the qualifier to turn to his support box with clenched fist having set up two set points in his favour.

Within seconds his supporters in the crowd were on their feet to celebrate Lokoli levelling the match. 

Ruud turned up the heat and chalked up a 2-1 break, which Lokoli erased with an "Allez!", threatening to make this a very uncomfortable afternoon for the No.4 seed.

Instead, Ruud locked in with all-consuming consistency. The Norwegian has featured in three of the past five Grand Slam finals, in contrast to Lokoli, who is still seeking his first ATP-level victory.

The difference in experience was starting to show and at 2-2 in the fourth set Ruud threaded a sweetly-struck backhand pass, which acted as the catalyst for him to motor into the second round.

"I started great, Laurent was maybe a little nervous, maybe the first time he played on a big court like this. For me it was also the first time on Court One too, so I was a little nervous, but I had a great time," reflected Ruud.

"I started well, which helped calm the nerves and he bounced back without any pressure, kind of effortless tennis.

"Sometimes on the grass it goes quick, sometimes fast. I just tried to stay in there. I'm just very happy to be through to the second round."

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