Round-robin play concludes on Friday at the World Tour Finals as Novak Djokovic seeks to clinch the year-end No. 1 ranking and Stan Wawrinka aims to join him in the semifinals.

Novak Djokovic v. Tomas Berdych

Tomas Berdych really put himself in a disadvantageous position after losing his first round-robin match against Stan Wawrinka, knowing that a berth in the semifinals would likely to require him to beat Marin Cilic and Novak Djokovic.

Berdych enters their round robin match tomorrow having beaten his Serbian foe only twice in 18 previous meetings. Making things even worse for Berdych is that he has an 0-5 record against Djokovic on indoor hard courts.

Their most recent meeting won’t give Berdych any fond memories either. In the Beijing final that these two contested earlier this fall, Djokovic led 6-0 5-0 and had match point to clinch the double bagel. Fortunately for Berdych and all those watching, he was able to pick up two games at the end of the match.

Their head-to-head reflects one of the most important realities in tennis:  matchups matter. Djokovic’s defensive prowess makes it close to impossible for Berdych to execute his first-strike game plan. Djokovic gets his racket on balls that no other opponent would, forces Berdych to play that one extra shot, and is able to turn defense into offense with one strike. This relenting resistance is something that Berdych has not been able to overcome on most occasions.

If Berdych wants to win this match, he needs to take control of as many points as possible, look to beat Djokovic down the middle of the court and to the sidelines, and get to the net. Long baseline rallies are ones that Djokovic will win all day every day.

Berdych has had another consistent season, but don’t expect it to last past Friday.

Prediction: Djokovic in two sets

Marin Cilic v. Stan Wawrinka

In a match pitting the two first-time Grand Slam champions, Australian Open winner Marin Cilic and U. S. Open winner Stan Wawrinka will face off in the final round-robin match of the World Tour Finals.

This match appeared to be one of the most compelling ones entering the tournament, but Cilic’s second-rate performances in his first two round-robin matches makes it far less intriguing than many thought it would be.

Cilic has only six games in his two matches against Tomas Berdych and Marin Cilic. He hasn’t sounded overly disappointed about his time in London and has probably accepted the fact that he’s a bit burnt out and his season has run its course.

Wawrinka still hasn’t qualified for the semifinals but can essentially guarantee his spot in the weekend with a win over Cilic, assuming Djokovic doesn’t suffer a huge upset against Berdych.

The last time these two played was in the round of 16 of the Cincinnati Masters, a match that Wawrinka won in three sets. Wawrinka has won their last three matches and leads the head-to-head 7-2 overall.

The strategy for Wawrinka is simple. Knowing that Cilic has been unable to keep the ball in play this week, as long as Wawrinka plays steady and doesn’t start pushing and becoming overly passive, he’ll be in fine shape. Unless Cilic can restore the level of consistency that saw him through to his first Grand Slam title, this is going to be one-way traffic for Wawrinka. He is prone to bouts of erratic play, but look for him to maintain more control over his game tomorrow, knowing he is playing an out-of-form opponent.

There’s very little reason to believe that Cilic is going be able turn things around tomorrow. His season has been a groundbreaking one, but like Berdych, it is likely to come to a finish tomorrow.

Prediction: Wawrinka in two sets