Once again, for the third consecutive year, Novak Djokovic is through to the final of the Barclays ATP World Tour Finals in London, where he will meet one of his greatest rivals for the 37th time on the professional tour. The Federer-Djokovic rivalry extends back to 2006 and has reached a head-to-head record of 19-17.

The top seed faced the sternest test of his WTF campaign when he stepped across the court from an inspired Kei Nishikori. Djokovic, who came into this match having just been crowned the year-end No. 1 player, survived a mid-match lapse in focus to rebound and close out the contest in dominant fashion in the deciding set. The match ended 6-1, 3-6, 6-0 in 1 hour and 27 minutes.

Djokovic has now advanced his indoor streak to 31 consecutive wins, which date back to a 2012 loss to Sam Querrey at the Paris Bercy. He dropped a mere nine games in the round robin stage and lost his first set this week against Nishikori.

“I was fortunate because in the beginning of the third set, he had break points,” said Djokovic. “If he broke me, the match could have gone either way. I managed to find that little bit of strength and get a win today. Tomorrow is the last match of the season. Of course it’s one of the biggest tournaments in the world. This is already the biggest possible motivation. I will try to give everything I have.”

In what was undoubtedly the most enthralling match of the year-end championships so far this season, Federer and Wawrinka contested a three-set battle that featured an assortment of controversy, overrules, momentum shifts, and heartbreak, before Federer eventually struck the final blow for a 4-6, 7-5, 7-6(6) score.

Having already contested five separate matches against each other this season, Djokovic and Federer are hardly strangers to the other’s game. Federer holds a 3-2 edge this season; however, both men showed slight weaknesses in their semi-final matches, making it near impossible to confidently predict a victor in tomorrow’s encounter. With Djokovic’s 31-match indoor streak on the line, he has proven to be the more consistent player on this surface.

Prediction: Novak Djokovic in Three Sets