World number one Novak Djokovic required just one set to qualify for the semi-finals, and proceed to win his final group match 6-3 7-5.
The Serbian national joins Roger Federer in the last four at the ATP World Tour Finals with victory over Tomas Berdych in London.
He will face Rafael Nadal in Saturday’s semi-final, before Federer takes on Andy Murray or Stan Wawrinka.
It was always going to be a tall order for Berdych to claim the straight-sets win he needed to edge out Djokovic – the Czech had won two of 22 matches against the Serb, and none of 17 on hard courts.
He managed to recover an early break of serve but Djokovic moved ahead again and clinched the set he required after 42 minutes.
Berdych, 30, still had the £109,000 on offer for every round-robin win to play for and again fought back from a break down in the second, but Djokovic broke for the fourth time at 5-5 and closed it out.
“I just waited for a game with more second-serve opportunities and that’s what happened at 5-5,” said Djokovic.
“It was a solid performance, I think. We both can have done better. It’s been a long year and we did our best.
“Rafa has another match tomorrow and I’m going to watch that a little bit with my team and prepare.
“Hopefully I’ll be able to perform at my best because that’s what’s needed to win against him.”