For more than a decade, Roger Federer has felt the fervent support of the Wimbledon crowd. But the Swiss legend may experience some uneven cheers when he meets emerging fan-favorite Marcus Willis in the second round Wednesday at the All England Club in London. 

Willis, born in nearby Slough, is the big underdog story of the Championships. After earning just 220 pounds ($293.62) in prize money in 2016, the 25-year-old's earnings have  jumped to 50,000 pounds ($66,740) with his straight-sets win in the first round. A tennis instructor making about $40 an hour giving tennis lessons, Willis will be living the dream when he steps on Center Court against Federer. 

As for Federer, the veteran star swept Argentina’s Guido Pella in straight sets, 7-6 (7-5) 7-6 (7-3) 6-3, by firing off 12 aces, including two to claim the last two points.That big serve allowed Federer to ease some pressure on his body after back and knee injuries derailed the first half of his season. 

But Federer’s serve also masked his 1-for-9 rate on break points and 18 unforced errors against the No. 52-ranked Pella, who has just three wins against top 25 players and hasn’t reached far enough into tournaments to challenge anyone in the top 10.

Federer, while clearly excited to be back at the venue that’s made him a legend, did express some doubt about his fitness after the match.

"I felt great," he said to BBC Sport. "I'm so happy to be here. I have worked hard since February to be here and hoped not to miss Wimbledon and to be here fully fit, so we will see if I am."

Willis, a local tennis instructor, faced a harrowing gauntlet just for the right to play Federer. He came from a set down to defeat No. 99 Yuichi Sugita. He then held off Andrey Rublev, an 18-year-old Russian ranked No. 153.

His final match came against Russia's Daniil Medvedev (No. 228) and, despite losing the first set, he rallied again for a victory.

In his first ever Grand Slam match, Willis defeated No. 54 Ricardas Berankis of Lithuania 6-3 6-3 6-4. He saved 19-of-20 break points.

"This match is different. It's picked up momentum. People will hear about it," Federer said of Willis. "Naturally they're going to support him — rightfully so, because I think it's a very cool story.

"I saw him play today. He plays well. Plus, he is serve and volleying, which I love to see. He came up with some great, great shots. To beat a guy of Berankis' caliber in straight sets shows you how tough he is.

"It was cool to see how pumped up he was. There's a lot of cool things that are part of the story. I probably don't even know where to start. I just like the idea of him."

Federer vs. Willis is the third match on Center Court. Agnieszka Radwanska vs. Kateryna Kozlovo kicks it off at 8:00 a.m. ET, followed by Novak  Djokovic vs. Adrian Mannarino. Federer and Willis should probably get on the court somewhere between 11:30 a.m and 2:00 p.m. Afternoon rain is expected in London. 

Prediction: Momentum and heart are certainly in Willis’ favor, but Federer is one of the all-time greatest tennis players and he's playing on a preferred surface. Expect a quick result over three sets for Federer, and for Willis to take a lot of chances while delighting the crowd. 

TV Channel: ESPN

Live Stream: ESPN3