![Novak Djokovic overcame big-hitting Milos Raonic at the ATP Finals in London, but victory was anything but straightforward.](https://media.cnn.com/api/v1/images/stellar/prod/161115213610-djokovic-atp-finals-celebration-tease-image.jpg?q=w_2607,h_1735,x_0,y_0,c_fill/h_447)
Novak Djokovic overcame big-hitting Milos Raonic at the ATP Finals in London, but victory was anything but straightforward.
![Djokovic, a five-time ATP Finals champion, had beaten Raonic in all seven of their previous meetings, but break point opportunities for Raonic in both of the world No. 2's opening service games showed the Canadian was in the mood to play.](https://media.cnn.com/api/v1/images/stellar/prod/161115213417-raonic-atp-world-tour-finals.jpg?q=w_3438,h_2292,x_0,y_0,c_fill/h_447)
Djokovic, a five-time ATP Finals champion, had beaten Raonic in all seven of their previous meetings, but break point opportunities for Raonic in both of the world No. 2's opening service games showed the Canadian was in the mood to play.
![Raonic couldn't take them, but this quickly proved the most tightly-fought contest of the tournament so far. Djokovic might have waved amicably to Serbian flagbearers as he made his way onto court, but as his opponent continued to pump huge 140mph serves past him, the world No. 2 began to bristle.](https://media.cnn.com/api/v1/images/stellar/prod/161115213607-raonic-serve-atp-tour-finals.jpg?q=w_4909,h_3280,x_0,y_0,c_fill/h_447)
Raonic couldn't take them, but this quickly proved the most tightly-fought contest of the tournament so far. Djokovic might have waved amicably to Serbian flagbearers as he made his way onto court, but as his opponent continued to pump huge 140mph serves past him, the world No. 2 began to bristle.
![In typical fashion, Djokovic remained resilient. While Raonic hit eight aces in the first set, winning 88% of points on his first serve, it was Djokovic who held his nerve in the tie break -- taking the set 7-6 (8-6).](https://media.cnn.com/api/v1/images/stellar/prod/161115213609-novak-djokovic-stretch-atp-world-tour-finals.jpg?q=w_4858,h_3239,x_0,y_0,c_fill/h_447)
In typical fashion, Djokovic remained resilient. While Raonic hit eight aces in the first set, winning 88% of points on his first serve, it was Djokovic who held his nerve in the tie break -- taking the set 7-6 (8-6).
![After 64 minutes on court, Raonic had given it everything but it still didn't prove enough. Three break point opportunities had come and gone, and the Djokovic wheel was beginning to turn.](https://media.cnn.com/api/v1/images/stellar/prod/161115215347-raonic-tired-atp-finals.jpg?q=w_2234,h_1487,x_0,y_0,c_fill/h_447)
After 64 minutes on court, Raonic had given it everything but it still didn't prove enough. Three break point opportunities had come and gone, and the Djokovic wheel was beginning to turn.
![But how things can change in six months. When Raonic was broken early in the second set, he might previously have crumbled; instead, the 25-year-old Canadian fought back to set point in the second... <br />](https://media.cnn.com/api/v1/images/stellar/prod/161115220053-raonic-fist-pump-atp-finals.jpg?q=w_4483,h_2984,x_0,y_0,c_fill/h_447)
But how things can change in six months. When Raonic was broken early in the second set, he might previously have crumbled; instead, the 25-year-old Canadian fought back to set point in the second...
![And yet Djokovic was not to be denied. The Serbian held out, forced another tie-break, and duly won the match [7-6, 7-6]. Will the five-time ATP Finals champion strike once again in 2016? Have your say on<a target="_blank" target="_blank"> CNN Sport. </a>](https://media.cnn.com/api/v1/images/stellar/prod/161115213415-djokovic-atp-world-tour-finals.jpg?q=w_1428,h_983,x_0,y_0,c_fill/h_447)
And yet Djokovic was not to be denied. The Serbian held out, forced another tie-break, and duly won the match [7-6, 7-6]. Will the five-time ATP Finals champion strike once again in 2016? Have your say on CNN Sport.