Novak Djokovic remains firmly on course to win a hat-trick of ATP World Tour Finals titles after overcoming Kei Nishikori 6-1 3-6 6-0 in a topsy-turvy semi-final encounter, but the world no.1 may have lost some fans along the way.
The Finals have thus far been defined by the amount of easy victories from the top stars, and this last four encounter looked like going the very same way as Djokovic blew his Japanese opponent away in the first set.
However the second set saw Nishikori, who reached this stage on the back of finishing runner-up to Group B winner Roger Federer, displayed his growing ability with the help of his vocal support inside the O2 Arena.
Points had been few and far between for the 24-year-old in the opening exchanges, so his fans were delighted when he broke-back early in the second set against the Serb.
Djokovic, however, was less than impressed when his double fault which secured the break was met with a chorus of cheers. After having things so easy in the Finals so far - with simple wins over Tomas Berdych, Stanislas Wawrinka and Marin Cilic seeing him drop just nine points in the three matches combined - the world no.1 lost his cool as momentum, for once, swung against him.
The 27-year-old proceeded to sarcastically clap the fans and shake his head at their support for Nishikori. Needless to say his anger failed to make matters as the actions were met with a number of boos, if anything it led to the London fans pledging further support to the underdog in the hope of seeing a better contest.
Indeed Djokovic's outburst appeared to disrupt his concentration as Nishikori got himself back into the match. A further break in serve for the youngster secured him an eqaulising set, nobody else had managed such a feat against the seven-time Grand Slam champion in the Finals this year.
However, with the opportunity for reflection and calm during the short interval before the decider, Djokovic got back to his best and ended up repeating the levels he had shown in the first set.
Once again he blew away Nishikori with a number of winners from his own serve whilst also solidifying his defences.
What, for a time, looked like it could be the classic the crowd had hoped for, the match in fact turned out to be another simple win. Djokovic hasn't lost an indoor match for over two years and he'll fancy his chances of continuing that record in Sunday's final.
One of the Swiss pair, Federer or Stanislas Wawrinka, will attempt to prevent the favourite from lifting the ATP World Tour Finals trophy for a third successive year.