Soon-to-be-Sir Andy Murray appears to be on his way to a coronation in London -- or, at the very least, knighthood.

He has won 20 consecutive matches, has snatched the No. 1 ranking from Novak Djokovic and is bidding to run away and hide at these Barclays ATP World Tour Finals.

Still, history -- and this is a sprawling city with more than most -- suggests there could be some drama in the offing. For instance, Murray has qualified for this year-end event nine times but has never won it. And consider that Wednesday's round-robin opponent, Kei Nishikori, poses a serious threat. Two of their three matches this year went the maximum five sets, with Nishikori taking the most recent, in the quarterfinals of the US Open.

This match can be seen on ESPN3 at 9 a.m. ET.

The 26-year-old from Japan, who could conceivably finish the year at a career-high No. 3, wrecked US Open champion Stan Wawrinka 6-2, 6-3 in the first round-robin match, which clearly caught Murray's attention.

"I didn't see the match, but he obviously must have played very well," Murray said in his news conference after defeating Marin Cilic by a similar count. "To win against a player like Stan with that score line; I don't think Stan had really any chances on Kei's serve, either.

Kei Nishikori needed just over an hour to take down Stan Wawrinka earlier this week at the ATP World Tour Finals. Andrew Cowie/Colorsport/Icon Sportswire

"I would say this is probably his best year that he's had on the tour. He's one of the best players in the world. He's been playing very well the last few months especially."

This, of course, Murray knows firsthand. He also understands that the winner will be 2-0 in round-robin play and in a commanding position to advance to Saturday's semifinals.

Murray won the first two meetings earlier this year, prevailing in a five-setter in Davis Cup play and, more recently, at the Olympics in Rio de Janeiro, winning a semifinal tilt more comfortably, 6-1, 6-4.

"I had a tough loss in Rio," Nishikori admitted. "But US Open and Davis Cup, we played some good matches. I feel more chance to win the match against Andy. Yeah, for sure I have to play well and play 100 percent to beat Andy. This [Wawrinka] match will help, for sure, for next match."

Before the Olympics, Nishikori also beat Wawrinka in the semifinals at Toronto, ending a run of 0-for-16 against top-five opponents. They ran into each other again in the US Open semifinals, with eventual champion Wawrinka getting the better of him.

The London loss, though, puts Wawrinka in a difficult spot when he faces Cilic in the evening match (3 p.m. ET on WatchESPN). They're both 0-1, and the loser is in deep, deep trouble.

"I was expecting a good match," Wawrinka said of his meeting with Nishikori. "Didn't happen today. Not the first time that I lose the first match here. Last year, I lost against Rafa, really bad match.

"I'm sure I still have something inside me to play some great tennis before the end of the year, so I'm going to try everything for that in the next match."

While Wawrinka will finish the year as the top-ranked Swiss player for the first time, you have to feel for him. In three previous appearances in London, he was 6-6 -- with two losses each against Djokovic, Roger Federer and Rafael Nadal. With the latter two sitting this one out and Djokovic in the other group, Wawrinka seemed to have a reasonable path to reach the semifinals.

Cilic, meanwhile, needs to quickly ramp up his game. The 28-year-old from Croatia immediately forced two break points in his first match against Murray but lost the opening game -- and his subsequent serve.

"Obviously [it's] tougher to start straightaway with matches like these against the best guys. I'm not so used to it," Cilic said afterward. "That's something I guess quite new for me. Most of the tournaments I'm playing them third, fourth round at least."

Cilic is 0-4 in year-end play after going 0-3 in his 2014 debut. Both he and Wawrinka are US Open champions, but one of them could be looking at the end of his season.