Stan Wawrinka and Rafael Nadal face off for the 17th time in their careers in their first Round Robin match in the Ilie Nastase group at the ATP World Tour Finals. Nadal leads 13-3, but has lost three of the last four encounters.

(4) Stan Wawrinka - (6) Rafael Nadal

Wawrinka makes his third straight appearance at the year-end Tour Finals. The two-time Grand Slam champion has advanced out of the Round Robin stage to the semifinals each of the past two years. He starts this week with relatively good form after a semifinal showing in Paris in his last tournament. Wawrinka ended Novak Djokovic's consecutive sets won streak at 29 in that match, but ultimately lost in three sets. Stan has been solid at indoor events this season, going 11-4. That includes a title in Rotterdam in February.

Nadal is back at the Tour Finals after a one year absence. In his last appearance at the event, he made the final in 2013. He beat Roger Federer in the semifinals that year before losing to Djokovic in straight sets in the final. Nadal has a good track record at this event having made it out of the Round Robin stage four times in six trips to the Tour Finals. His form headed into this week is also pretty solid. He did lose to Wawrinka in the Paris quarterfinals, but does sport a 7-2 mark on indoor hard courts in 2015. Most of those wins came in Basel where he made the final and lost to Federer 3-6, 7-5, 3-6.

One gets the impression that Nadal is grateful to have improved his form recently and put himself in position to compete against the best this week. Over the weekend, he told reporters as much saying, "After a tough year, if you’re able to arrive at this tournament with that number that says that the level is still there. I need to keep playing the way that I’m playing the last month and a half. I think like this I’m going to be in a good position.”

Head-to-Head Meetings

Monday's match will be the third between Wawrinka and Nadal in the last two months and fourth overall this season. Wawrinka owns two wins in those three matches this season. The last coming in Paris and the first coming in Rome on clay back in May. Nadal's lone win over the Swiss this season came at the Shanghai Masters where he annihilated Wawrinka 6-2, 6-1. They have met at the Tour Finals once in 2013. It was the Spaniard who came out on top 7-6, 7-6 in that match during Round Robin play. That match and the one this year in Paris are the only two career battles that have taken place on an indoor surface between these two.

Expectations On Monday

Looking back to their last meeting in Paris, one should reasonably expect another tight battle with momentum swings. In that match, Nadal blew a break lead in the opening set as he failed to serve the set out at 5-4. Wawrinka returned the favor in the second set at the identical score line. In both cases though, the Swiss was the stronger player when it mattered in the tie breakers. There was little to separate the two though with the breakers going 10-8 and 9-7 to Wawrinka. The plus for both players is there will be no late night finish as they had in Paris where their match ended after 1:00 a.m. in Paris. Wawrinka and Nadal are scheduled as the first night session match on Monday to start around 8:00pm London time.

Strategy Session

The conditions at The O2 Arena look to be playing fairly slow based on the opening day's play. Serve can still control play, but it does not appear that there will be a ton of cheap points off of aces based on the court speed shown on Sunday. That should help Nadal some in this match-up as he will be able to get Wawrinka into rallies if the Swiss is unable to secure easy points on serve. Wawrinka has the ground game to beat the best as he has shown in winning two Grand Slams in recent years against the best of the best in Djokovic. The Swiss often goes for the big shot which brings that high risk, high reward outcome. When his forehand and backhand are cooking, he hits marvelous winners. When he misses though, the errors can flow often to the detriment of the match.

Nadal of course will not normally control a match with big serving, but the lefty from Spain can effectively use different angles and speeds to set himself up in good positions off the return of his opponent. That is his key. Giving Wawrinka minimal looks at his second serve would also be a big plus in the win column for Nadal. With the slower conditions, expect to see a baseline battle unfold in this one. The motivation should be high for both, but coming off the loss, Nadal may have a little more to prove in this one. If he can keep his nerve if he is in position to win sets this time around, he could find himself off to a winning start.

Prediction: Nadal wins in three sets.