WIMBLEDON -- Kevin Anderson is clearly enjoying his tennis, but for now he is just happy to have a day off.

Despite having to play for a third successive day at Wimbledon, Anderson advanced to Round 4 for the fourth time in five years with a comprehensive 6-3, 7-5, 7-5 victory over No. 25 seed Philipp Kohlschreiber Friday.

A keen guitarist, Anderson will celebrate his latest victory by watching American singer-songwriter Jack Johnson perform in London. He may even serenade the leafy streets surrounding the All England Club himself, too.

"Maybe I'll play a few of his songs today," Anderson said. "I have my guitar with me, and I have a couple days off, so maybe now I'll get in a bit more guitar time!"

The big-serving South African, who suffered the schedule blip on the back of Wednesday's rain delay, rattled down 22 aces, 42 winners and constricted his German opponent with an average first serve speed of over 127 mph.

Even Kohlschreiber admitted, at times, Anderson had been unplayable: the serve had been too strong, nigh on impenetrable on the sun-drenched lawn of Court No. 2.

The Johannesburg native is playing some of the best tennis of his career -- he said as much Thursday following his second round win over Andreas Seppi -- and it showed as he roared in celebration before jovially throwing his sweatbands into the applauding crowd. Now he has eyes on a first quarterfinal appearance at the All England Club.

"I definitely feel I have pushed through in the level of my game. Even though I'm 32, I still feel like my best tennis is ahead of me," Anderson said. "I work very hard in order to get there, and I feel like I'm making strides in that area.

"In a match like today it's very rewarding for me to see those constant improvements taking place. That's something that I hopefully will be able to continue doing for a long period of time to come."

Kevin Anderson roars in celebration after beating Philipp Kohlschreiber at Wimbledon. Michael Steele/Getty Images

Anderson could potentially meet defending champion Roger Federer in the last eight and, while Kohlschreiber admitted his victorious opponent possesses the "big game" to upset the eight-time winner, he must first negotiate a tricky fourth round clash with Gael Monfils on Monday.

Monfils has won all five of their previous meetings, although the pair have never faced on grass and last played each other in 2016.

"It will be an interesting adjustment to see what happens," Anderson said. "I feel like on other surfaces he does such a great job of retrieving, absorbing pace very well. He stands quite far back behind the baseline. I feel it's a little tougher to do on grass."

Anderson will be wary of Monfils and not just because of his record against him: the Frenchman overcame injury to topple another big server in America's Sam Querrey -- who ended Andy Murray's reign as defending champion last year -- on Centre Court earlier Friday.

Monfils, 31, defeated Richard Gasquet and Paolo Lorenzi ahead of his match with Querrey but expects a rejuvenated Anderson to pose a real threat in the second week.

"He's going for it," Monfils said of him. "It will be a tough one, even more on grass. Kevin has been maintaining his level for a while now. He's a very solid playe, no more ups and down. He's always strong and I think his belief is stronger than ever."