2. Andy Murray d. Kei Nishikori 6-7(9), 6-4, 6-4/RR/Barclays ATP World Tour Finals

Novak Djokovic was the final obstacle Andy Murray faced during his historic run to year-end No. 1 in the Emirates ATP Rankings. But looking back on it, Kei Nishikori might have been Murray’s trickiest opponent during the Barclays ATP World Tour Finals in London.

Coming into their round-robin match, Murray had been on a roll. He’d won 20 consecutive matches, including back-to-back-to-back-to-back titles in Beijing, Shanghai, Vienna and Paris. But before Murray stopped losing this season, Nishikori had been one of the few players who had figured out how to beat him during the second half of the season. And he upset Murray on one of tennis’ biggest stages: US Open quarter-finals, Arthur Ashe Stadium.

The theatrics set, the players delivered at The O2. They fought for 85 minutes in the opening set, exchanging hot shot after hot shot, especially during the 20-point tie-break. Murray saved four set points, Nishikori, three. But the Japanese would finally win the opener to make it three consecutive sets against Murray.

The Scot would answer, though. He took the second set in 53 minutes, breaking Nishikori at 4-4 before serving out the set. But when it came time to serve for the match, Murray faltered at 5-2. He’d make it up it at 5-4, though, and remain unbeaten in round-robin play. Nishikori had the level to beat the World No. 1 but couldn’t sustain it.

“It never feels good after losing the match,” said Nishikori. “I know it was close. I mean, I’m definitely disappointed… I think it was great match, both of us.”

1. Andy Murray d. Milos Raonic 5-7, 7-6(5), 7-6(9)/SF/Barclays ATP World Tour Finals

More hardly could have been on the line when Andy Murray and Milos Raonic met during the semi-finals of the Barclays ATP World Tour Finals in London.

Murray, the newly-annointed World No. 1, was trying to extend his 22-match win streak, reach his first final at The O2 and complete only one of the hardest tasks in tennis: Finish No. 1 in the year-end Emirates ATP Rankings.

Only sixteen men since 1973 had ended the calendar year on top before this season, and the Scot was just two wins away from joining that elite club when he faced Raonic. The pressure was on, too, as World No. 2 Novak Djokovic had also reached the last four in London. Beat Raonic, and Murray still controlled his fate, but lose, and the top spot was Djokovic’s to take.

Raonic had already faced the Serbian in London, falling in a tight 7-6(6), 7-6(5) round-robin match. Against Murray, the Canadian was hoping to win those few crucial points and assure himself a career-best year-end No. 3 in the Emirates ATP Rankings.

He had already come oh so close to beating Murray in 2016. Raonic was up two sets to one in the semi-finals of the Australian Open. At The Queen’s Club final, he led by a set and a break. But both times, Murray turned back Raonic’s power tennis.

At The O2, Raonic was again the early starter, taking the opener 7-5. He broke early in the second set to get within four consecutive holds of his first London final. But Murray came back and the two were tied at 4-all in the third set.

What ensued next was the most unpredictable stretch of the tournament: Four consecutive service breaks. First Raonic couldn’t hold to get to 5-4, then Murray couldn’t hold to win the match. Then it was the Canadian’s turn again, dropping his serve at 5-all. Then Murray, incredibly, was broken at 6-5, his second attempt to serve out the match. So they headed to tennis’ most dramatic moment, a tie-break in the final set.

Raonic saved three match points and had his own match point at 9/8 but Murray cut a backhand volley to even the tie-break at 9/9. Two points later, he’d point to his heart in celebration.

On Wednesday in London, Murray and Kei Nishikori had set the record for the longest three-set match in season finale history, three hours, 20 minutes. But four days later, Murray and Raonic had broken the record with their three-hour and 38-minute semi-final.

Murray’s 24-match win streak. His first Barclays ATP World Tour Finals title. His first year-end finish at No. 1 in the Emirates ATP Rankings. In the semi-finals against Raonic, they were all a swing away from not happening in 2016.

Coming Wednesday: The best Grand Slam matches of 2016.