The question was posed again this fortnight, as it has been in the past: Is this the time Bulgarian Grigor Dimitrov, whose one-handed backhand and flair can resemble Roger Federer's game, will challenge the Swiss great?

But Federer answered the question again on Monday with a firm, “Not yet.” The seven-time champion extended his dominance against the Bulgarian and in Wimbledon fourth-round matches, beating Dimitrov 6-4, 6-2, 6-4 to move into his 15th Wimbledon quarter-final. Federer now stands alone atop the Open Era list for most Wimbledon quarter-final appearances.

Most Wimbledon quarter-final appearances (Open Era)

The 35 year old advances to his 50th Grand Slam quarter-final, another best in the Open Era.

Most Grand Slam quarter-final appearances (Open Era)

Federer is now 6-0 against Dimitrov in their FedEx ATP Head2Head series. The Swiss right-hander has won all but two of the 16 sets they've played since their first meeting at 2013 Swiss Indoors Basel.

Dimitrov hadn't dropped a set during his first three Wimbledon matches and the 2014 Wimbledon semi-finalist had looked primed to challenge Federer. But the third seed was nearly untouchable in the familiar Centre Court environment.

The two exchanged holds until 4-4 in the first set, when Federer stepped up to break for a 5-4 lead. He'd serve the set out to love. Federer quickly pounced in the second set, seeing two break points at 2-2 after Dimitrov double faulted. The Bulgarian would finish with seven double faults for the match, compared to seven aces.

“I'm disappointed in myself that I couldn't play better. I did a lot of unforced errors, and my first serve was not on point. Without those weapons, it's never easy to play against him,” Dimitrov said.

And Federer would need only one break point in that fifth game, converting it when Dimitrov slapped a forehand wide. The 26-year-old Dimitrov struggled to challenge Federer at all in his service games. At 6-4, 4-2, Federer's average service game was lasting only one minute and 21 seconds. For the match, the Swiss right-hander landed 70 per cent of his first serves and won 75 per cent of his service points.

“I can look at this quarter-final in a totally relaxed fashion. Physically I'm not fighting anything like last year with my knee. I'm ready to go this afternoon if I have to, which is great, but I don't have to. I think that's a great bonus,” Federer said. “Then again, the best players are left in the draw. It's going to be a tough one. I'm aware of that. That's why I can't think too far ahead. I think it's going to be a tough finish to this tournament.”

The third-seeded Federer has yet to drop a set this fortnight, but he will face a stern test in the quarter-finals. Federer will meet 2016 finalist Milos Raonic , who held his nerve – saving 14 of 17 break points – to overcome #NextGenATP German Alexander Zverev 6-4, 5-7, 6-4, 5-7, 6-1 in three hours and 23 minutes.

Tenth seed Zverev led by a set and 3-1 before sixth seed Raonic started his fightback, eventually finishing with 23 aces among 61 winners. There were only 17 rallies of nine shots or more.

Raonic beat Federer in last year's semi-final to reach his maiden Grand Slam title match, but Federer leads their FedEx ATP Head2Head series 9-3. Asked to compare his game from a year ago to now, Raonic said, “I feel like as a shot-for-shot player I'm better. I just feel like I'm still trying to find that rhythm that I had last year, playing a lot of matches consistently. It doesn't mean it can't come, but I've just got to be sharp each and every point during the next match.”