Top seed and four time champion Roger Federer beat arch nemesis Andy Murray for the fourth time in 10 career meetings, this time on Scot's home soil, to increase his chances of securing his place in the semifinals of the 2009 Barclays ATP World Tour Finals.

Re-live the action of this thrilling encounter, click here.

Federer started the match on a seemingly good note and pocketed a break in the opening game. However, Murray struck right back and levelled the set to then see his chances for the next golden break that came in the fourth game which the Scot consolidated by pocketing the opening set 6-3.

The second set saw a shift in momentum when Federer broke Murray in the sixth game to race to a 4-2 lead. Murray did make an attempt to get the break back but failed to match Federer's increased ferocity in points.

With the match going into the decider, Federer patiently awaited a decisive break and got not one but three, the last one in the end to fetch him the set and the victory with a 3-6, 6-3, 6-1 scoreline in almost two hours of play.

The win increased Federer's chances of making it to the semifinals of the event as both Murray and Del Potro are drawn to a close in the Group A standings after winning one match each.

The victory also meant , Federer will finish the year as No 1 in the rankings.

"It was one of my big goals for this season," said Federer "Especially after having a rough 2008, coming back this year and being able to dominate and play at the top when the depth in tennis is so, so great at the moment. I think it's a wonderful achievement. It's official. It's a wonderful feeling."

"It was probably the most double faults I served in a match maybe this year in the first set... I served pants," said dejected Murray.

He added "I made more mistakes than normal. I just didn't play well,I served so poorly that anyone would have looked good against me tonight."

Earlier in the day, U.S. Open champion Juan Martin Del Potro defied a spirited performance from the Spaniard Fernando Verdasco to secure a hard-fought 6-4, 3-6, 7-6(1) win after a marathon struggle of two hours and 24 minutes.

The day 4 of the Round Robin matches will feature Djokovic-Soderling clash, followed by Davydenko-Nadal encounter in the night session.