Andy Murray advanced to the semi-finals of the 2016 ATP World Tour Finals on Wednesday after a 6-7(9), 6-4, 6-4 win over Kei Nishikori saw the Scot collect his second victory of the round-robin stage at the O2 Arena in London.

The tournament’s top seed recovered from a tiebreak defeat in the opening set to prove his credentials as the sport’s in-form force and battled back to prove he’s still got a lot to fight for in the end-of-year contest.

Stanislas Wawrinka will meet Marin Cilic later on Wednesday as he looks to bounce back from the opening defeat he suffered at Nishikori’s hands in what’s now become a must-win fixture for the Swiss star.

Murray is now in prime place to top the John McEnroe group after maintaining a perfect record in the competition’s opening phase, although Wawrinka can slow his progress when they face off on Friday.

Read on for a breakdown of Wednesday’s group-stage results, complete with a roundup of the standings so far and a look toward Thursday’s ATP World Tour Finals schedule.

John McEnroe Group Standings

Pos Player Played Wins Losses 1. Andy Murray 2 2 0 2. Kei Nishikori 2 1 1 3. Marin Cilic 1 0 1 4. Stanislas Wawrinka 1 0 1

Ivan Lendl Group Standings

Pos Player Played Wins Losses 1 Novak Djokovic 2 2 0 2 Milos Raonic 2 1 1 3 Dominic Thiem 2 1 1 4 Gael Monfils 2 0 2

Recap

Murray enjoyed a fairly rudimentary run past Cilic in his opening match of the tournament, but Wednesday’s showdown with world No. 5 Nishikori proved to be a far more testing battle of wits in Greenwich.

The first set proved a particularly close-fought struggle as neither player gave up a serve and duelled to a tiebreak decider that Nishikori managed to tip in his favour 11-9.

Each player contributed 20 unforced errors apiece in the first set, per Flashscore.com, but the official ATP World Tour website detailed how Nishikori’s superior serving statistics just about tipped the opener in his favour.

Tennis writer David Law illustrated how Murray attempted to keep his cool in front of a home crowd, albeit unsuccessfully at times:

Trying to think of another player in history who reacts as sarcastically about his own errors as Andy Murray.

Nope.

— DavidLaw (@DavidLawTennis) November 16, 2016

Nishikori almost paid the price for underrating Murray’s determination during the tiebreaker, but a lunging cross-court shot from the Japanese contender eventually sealed a climactic first-set win.

Murray launched an immediate bounce back to form, however, and got the start to the second set he so dearly craved by handing Nishikori an instant setback, as pointed out by CNN:

That’s why he’s number one. Swiftly overcoming the disappointment of losing the first set, Murray has immediately broken back in the second. pic.twitter.com/Y6086mnIaW

— CNN Sport (@cnnsport) November 16, 2016

The Briton led 4-3 before conceding a serve of his own to level the score, except Murray made up for that error with a deep return to once again gain a game advantage and see out the second set 6-4.

The world No. 1 then picked up where he left off in the third set and collected another break of his foe to lead 2-1. However, it took some time for Murray to build on that cushion as the pair played out 13 points in the fourth game, with Murray saving two break points:

Nearly 3 hours old and it’s only 2-1 Murray in the 3rd.

— DavidLaw (@DavidLawTennis) November 16, 2016

It seemed as though Nishikori’s stamina was exhausted early on, though, and Murray’s instead rose to the fore as he battled 4-1 ahead and eventually clinched a four-game cushion just as the match looked done.

Nishikori didn’t go down without a fight, however, and ensured there was tension until the end thanks to his late three-game streak, but an overreaching forehand meant the streak ended and Murray sealed the 6-4 win.