Roger Federer produced an impressive display to gain revenge on Juan Martin Del Potro and book his place in the last four of the Paris Masters.
The 17-time Grand Slam winner had lost to Del Potro in the final of last week's Basel Open but turned the tables with a 6-3 4-6 6-3 victory.
Federer showed signs of his majestic former best in the opening set, producing a mix of drops, slices and changes of pace that were too much for Del Potro.
The Swiss ace broke early and never looked under threat on his own serve as he took it 6-3.
But the second set was a different story as Del Potro got a foothold in the match. It went with serve but after saving a set point at 6-5 down, Federer cracked and put a forehand into the net to lose it 7-5.
Federer made the first move in the decider as he broke Del Potro to love in game five but the big Argentine broke back immediately to level again at 3-3.
However, Federer responded in kind by breaking Del Potro again and after holding his own serve he slammed the door by breaking his opponent for the third game in a row to seal an excellent win.
"Probably has to be," Federer said when asked if the win - his first over top-10 opposition since January - had been his best of the season.
"I have had some decent matches along the way - maybe against less famous players than Juan Martin - so I'm happy it worked out well today.
"I think it was a good match from start to finish. That's definitely good for my confidence, because those are the kind of wins I need right now."
Federer will now take on Novak Djokovic in the semi-finals.
Second seed Djokovic wasted little time in storming into the last four with a comprehensive 6-1 6-4 victory over Stanislas Wawrinka.
Djokovic swept into a one-set lead in just 26 minutes after making light work of his Swiss opponent who was struggling to find his range.
Wawrinka settled into the second set and had four break points in the second game, but failed to make any of them count as he let Djokovic off the hook six times in total in the match.
Djokovic took full advantage to seal the victory for the loss of just five games.