Tomas Berdych remained in contention for a place in the semi-finals of the ATP World Tour Finals after cruising to a 6-4, 6-4 win over David Ferrer on Wednesday.
Berdych had lost his opening Group A match against Stanislas Wawrinka on Monday, but gave himself a shot at making the last four of the season-ending event by sweeping aside world number three Ferrer in one hour and 23 minutes at London's O2 Arena.
To have a chance of qualifying, the Czech fifth seed must now defeat world number one Rafael Nadal, who has already booked his spot in the semi-finals, in his final group match on Friday.
Ferrer looks certain to be eliminated after failing to win a set in either of his first two matches.
"It was not easy at all, you can see David is a great player," Berdych said.
"I'm happy with the way I played today and I'm looking forward to the next one.
"The serve was working really well today, that was the key. I made a lot of points from my serve so I could feel much better from the back."
The Spaniard had held a 7-3 head-to-head advantage over Berdych, with a victory in their last meeting just five days ago in the quarter-finals of the Paris Masters.
But Ferrer, a Tour Finals runner-up in 2007, looked fatigued after his run to the final in Paris on Sunday and Berdych easily secured his first win over the 31-year-old since a victory at this tournament in 2011.
Few matches at this year's Tour Finals will offer more of a contrast in styles than this one.
The towering Berdych possesses a huge serve and sporadically fierce ground-strokes, while the diminutive Ferrer relies on his tenacity and some clever shot selection.
But for all the obvious differences in their games, both are high-quality competitors and there was little to separate them in a tight first set.
The only break went Berdych's way in the ninth game when the Czech earned two break points and converted the second, following in a cross-court forehand with a volleyed winner, before easily serving out the set.
It was a similar story in the second set as Berdych continued to control the tempo, while Ferrer lacked the weapons and the energy to turn the tide.
Berdych landed the knockout blow with a break for a 5-4 lead when the harassed Ferrer missed a forehand.
There was little doubt about the outcome from there and Berdych sealed the win with a typically fearsome serve that left Ferrer rooted to the spot.