The second day of Group Boris Becker action got started with Marin Cilic taking on Jack Sock at the O2 Arena on Tuesday. Sock ended up prevailing with a 5-7, 6-2, 7-6 (4) victory, and the American is now 1-1 in group play.
Cilic will likely be very hard on himself for letting this one get away, as he was up 3-0 in the third set. A big server like that should always expect to close out a match when they are up a break, but the Croatian just couldn't get the job done.
To make matters worse, the 29-year-old was also up a mini-break in the third-set tiebreaker. Cilic is now 0-2 in group play and has a date with Roger Federer coming up. At this point, it's hard to imagine him leaving London with a win.
For Sock, this was yet another remarkable ride in what has been a wild end of the season. Last week, the American unexpectedly won the Paris Masters to earn himself a spot in this event. Heading into that tournament, the 25-year-old had no idea that playing this week was even a possibility.
Now Sock is showing off his fighter mentality, as he has turned into a player that can no longer be counted out in any situation.
His next opponent will be Alexander Zverev, and a victory over the 20-year-old could very well mean that Sock is heading to the semis.
If one thing is certain then that is the fact that nobody will want to face the American at that point. He is brimming with confidence and that forehand is looking as good as ever right now.
In the second singles match of the day, Roger Federer defeated Alexander Zverev 7-6 (6), 5-7, 6-1. Federer improved to 2-0 in Group Boris Becker, and he also secured a spot in the ATP Finals semis for the 14th time in his career.
While the third set might have been lopsided, Zverev definitely hung with Federer in this one. He took a set off of Roger and easily could have won the first as well.
The German might be a bit disappointed by how this played out, but the 20-year-old must forget about it fast. He has a meeting with Jack Sock on deck and the winner of that match will be heading to the semifinals. Zverev is 1-1 in two career meetings with the American.
For Federer, a match against Marin Cilic awaits. It won't mean much to either player, but that doesn't mean that the two of them won't play hard. It is, however, worth noting that Federer has beaten Cilic in seven of the eight meetings between the two players.