Why Murray and Djokovic might not prevail Saturday at Tour Finals

Incredibly enough, with two days left in the men's tennis season, we still don't know who will wind up with the No. 1 ranking.

No. 1 Andy Murray and No. 2 Novak Djokovic could meet in Sunday's championship for Barclays ATP World Tour Finals -- marking the first time in tournament history that two finalists would determine the No. 1 ranking.

In Saturday's semifinals at London's O2 Arena, Murray faces No. 4 Milos Raonic, and later Djokovic meets No. 5 Kei Nishikori.

After beating Stan Wawrinka 6-4, 6-2 Friday, Murray was asked if it mattered whether the pivotal match with Djokovic came sooner or later.

"I mean, there's a good chance that if I want to win the tournament, I would have to win against him," he told the media. "That would either be in the semis or the final. I don't think that makes a whole lot of difference.

"I'm certainly not taking anything for granted. I know it will be hard. But, yeah, I feel like my game's in a good place."

Here's a breakdown of the two semifinal matches:

Andy Murray versus Milos Raonic, 9 a.m. ET on ESPN3

Round-robin records: Murray 3-0; Raonic 2-1

Career head-to-head: Murray leads 8-3 (with three walkovers)

W2W4: Turns out, life atop the tennis universe hasn't been a burden after all. Murray won all three of his round-robin matches this week and five of six sets. And while he still seemed frazzled and frustrated at times (notably against Nishikori in his second match), he has largely contained his outbursts. It's that kind of cerebral composure that has historically been his biggest enemy. And when you factor in all that is on the line in London -- winning a first ATP Finals title, securing it in front of his home fans and holding on to the top ranking -- Murray deserves credit for the manner in which he swept his way to the final four -- the first time since 2008 he's reached the semifinals unbeaten.

Truth be told, it's never been better. Murray has won 22 consecutive matches, equaling his career best -- which came earlier this year. He was masterful against Wawrinka, but his opponent Saturday is also playing some of the finest tennis of his career. Raonic has crafted a stellar 52-15 record, and the faster courts and indoor conditions of the O2 Arena make his serve more lethal than it already is. He's slugged a tournament high 40 aces through three matches.

But more telling beyond this tangible stuff is the manner in which Raonic, who could end the season ranked a career-high No. 3, talks about playing big in the seminal moments, as he did in a must-win match against Dominic Thiem on Thursday: "There's a lot definitely to be proud of, playing under that kind of pressure, 'cause I really wanted to get out of the group stages and I wanted to give myself a chance in the semifinals," he said to the media after a straight-sets win that propelled him into the semifinals.

Murray is keenly aware Raonic took Djokovic to a pair of tiebreakers and is comfortable in this venue. "Yeah, you don't normally get loads of opportunities against the big servers," Murray said. "Then it comes down to when you do get those chances, whether you take them or not. And this year when I've played him, I've created a few opportunities in the matches. When they've come, I've been pretty clinical.

"I'll need to be the same tomorrow if I want to win."

Prediction: Murray in two.

Novak Djokovic versus Kei Nishikori, 3 p.m. ET on ESPN3

Round-robin records: Djokovic 3-0; Nishikori 1-2

Career head-to-head: Djokovic leads 10-2

W2W4: Finally, Djokovic will play someone who has a career win against him. He was 23-0 versus his round-robin group heading into the ATP World Tour Finals and swept his three matches this week. Nishikori has beaten Djokovic twice, most notably in the 2014 US Open semifinals. Nishikori has played strong tennis since the summer hard-court season began. In August, he took down Rafael Nadal to win bronze at the Rio Olympics, and then a few weeks later made the US Open semifinals. Nishikori came into the year-end championships just a couple of weeks removed from a finals appearance at the Swiss Indoors. In his opener this week, he manhandled Wawrinka and narrowly lost to Murray in a three-setter Wednesday.

But this matchup will likely be determined by Djokovic's state of mind. For a player who preaches harmony and relaxation, he has been on edge all week, snapping at chair umpires and smashing rackets. Nearly unbeatable through the French Open, Djokovic, who had a commanding lead in the rankings during the summer, has battled himself as much as his opponents in recent months. He squirrely existence has raised questions as to what (and why) his game has fallen. Nonetheless, after dropping the opening set to Thiem last Sunday, Djokovic sailed the rest of the way in London, including a one-hour shellacking of alternate David Goffin, who filled in for injured Gael Monfils on Thursday.

Remember, not only is the championship on the line, but so is the No. 1 ranking, an honor -- even if he has not admitted it -- Djokovic believes he deserves. For the first time since his tenure atop tennis began 223 weeks ago, few have questioned whether he is the best player in the game. But the feeling now is that as he closes in on 30 years old, his game has dropped, while the landscape is slowly shifting. Still, with two full days left in the regular season, Djokovic has corralled a final boost of intensity. "I can say from my perspective that I always try to really take the last drop of energy, whatever is left in my body, to perform as well as I can and finish off the season in the best possible way," he told the media after beating Goffin.

Prediction: Djokovic in three