Roger Federer’s prize for coming from behind to defeat Juan Martin del Potro in a deciding group match at the ATP World Tour Finals is yet another meeting with the recently confirmed year-end World No. 1 Rafael Nadal. The Swiss trailed Del Potro 3-0 in the final set on Saturday before coming through to take the contest and progress to a semifinal where he will take on his long-time foe for the 32nd time.

For Federer the statistics make grim reading. Nadal breezed through the round-robin stage of the showpiece event at London’s O2 Arena, winning all three matches against David Ferrer, Stanislas Wawrinka and Tomas Berdych. Nadal also holds a commanding 21-10 advantage in head-to-head meetings with Federer and has won all three matches the pair has played in 2013.

Federer, though, has been the dominant figure at the year-ending finals. While he has won the tournament a record six times, it is the only major event so far to elude Nadal. The 32-year-old has also won all four of his meetings with Nadal at the season finale. Yet, despite showing some improved form in recent weeks, as he has overcome a back problem that plagued him for much of a disappointing season, Federer is keen to approach the match as the underdog.

"I just have to have the right mindset to give it one last go, maybe play with a little less pressure than I have in previous matches with him," he said, according to Reuters.

"I just feel like I need to look at it more as being an underdog a little bit because of circumstances, because of my year, because of his year. Maybe that free swinging is what I kind of need to do a little bit more tomorrow."

Having failed to lift a title since winning the US Open in September, Nadal appears determined to end his incredible year on a high. And, speaking before the identity of his last-four opponent was known, he said that he would have to be at his best on the indoor surface to come out in top.

“Any opponent will be very difficult,” he said, according to the tournament website. “We are playing against the best players in the world. So if is del Potro, if is Federer, both players know very well how to beat me, on this surface especially. The only way to win the match of semi-finals is by playing my best match, playing fantastic tennis. I have one day off. One day tomorrow to keep playing well, keep trying to improve a little bit more."

After that tantalizing first semifinal, Novak Djokovic will go up against another Swiss in Stanislas Wawrinka. Having beaten Federer on the opening day, Djokovic went onto claim a clean sweep of his group with victories over Del Potro and Richard Gasquet. And, despite missing the chance to claim the year-end No. 1 honor for a third-straight year, he can still pick up the trophy at the season finale for a third time.

Wawrinka, meanwhile, is capping a breakthrough year with a stellar performance in London. In the semifinals the 28-year-old will be looking to replicate arguably his best ever match as well as avenging his most heartbreaking loss from when Djokovic came from two sets to one down to win their epic US Open semifinal  earlier this year.

Where to watch: The first semifinal between Rafael Nadal and Roger Federer will get underway at 9 a.m. ET, with the second between Novak Djokovic and Stanislas Wawrinka scheduled to begin at 3 p.m. ET. Both matches will be shown on ESPN2, with a live stream available on ESPN3