Rafael Nadal finished the round-robin group stage at the ATP World Tour Finals with a perfect 3-0 record thanks to a three-set victory over fellow Spaniard David Ferrer this afternoon.

The duo have met over 30 times on Tour, but today's match had little meaning due to the fact that Nadal had already secured top spot in the Ilie Nastase group and Ferrer had no chance of progressing after losing his first two matches against Andy Murray and Stanislas Wawrinka.

Still, it was a gripping contest as both men went all out for the win at the O2 Arena in London.

Nadal started the better, securing an early double-break to move 3-0 in front before Ferrer hit straight back with three games of his own to level the set.

Nadal then seemed to make a crucial break in the 11th game to go 6-5 in front, but he could not serve out the opener as Ferrer saved a set point before forcing a tie-break.

Ferrer had the momentum and it was he who triumphed in the breaker, moving 3-0 ahead with two mini-breaks before closing it out comfortably 7-2.

After five comfortable holds to start the second set, Ferrer saved a break point in the sixth game but could hold off Nadal two games later as the 14-time Grand Slam winner broke through and went on to serve out the set 6-3.

Ferrer was under the cosh at the start of the decider, but he managed to hold his serve in the first game after seven deuces and five break points for Nadal.

Normal service was resumed by both men in the middle part of the set as they continued to exchange lengthy rally after lengthy rally.

It was Nadal who made the crucial breakthrough in the ninth game, though, before serving it out 6-4 in a little over two-and-a-half hours.

Nadal already knew that he would be facing top-seed Novak Djokovic in the last four, while Roger Federer will be up against the winner of tonight's match between Murray and Wawrinka in Saturday's second semi.