As predicted, Kevin Anderson failed to cause much of an impact on Novak Djokovic's serve, winning just 14/65 return points (22%) to continue his dire return data against the Serb, while Roger Federer managed to break Kei Nishikori three times in 11 return games to continue his propensity to break the Japanese man more than average.
The towering South Africa showed great athleticism to put away a backhand volley at the net and had a set point when Djokovic drilled a backhand wide, but the 14-time grand slam champion's serve got him out of a hole. He went up a break at the start of the second set, but then trailed 4-1 in the tiebreaker.
Yet the eighth seed from Japan saw his advantage wiped out in a hurry as Federer roared back to set up a last-four clash with Borna Coric, who had defeated Australian Matthew Ebden 7-5 6-4 earlier in the day.
Federer takes to the court second on Saturday's schedule, which has a more pleasant feel to it from a start time perspective, with this starting at 1pm United Kingdom time, after Alexander Zverev versus Novak Djokovic, which begins at 930am.
Djokovic and Zverev met on clay in the final of the Rome Masters in May last year, the 21-year-old German winning 6-4, 6-3.
Zverev has been very impressive this week having not dropped a set and neither has Novak, but Djokovic is playing beautifully.
"It was a different surface", Djokovic said of their previous match.
Federer had to play catch-up in the tie break and said afterwards that he was relieved to avoid another three-setter. "I wasn't, I feel like, playing as well as I'm playing today".
"It means a lot because I have kind of played only the biggest tournaments", Zverev said.
Earlier, fourth-seeded Alexander Zverev secured a spot in next month's ATP Finals with a 6-4, 6-4 quarterfinal win over Kyle Edmund. "It's going to be definitely a close match".