Marin Cilic
7 2 6

Jack Sock
5 6 7



Afternoon. Time for some tennis!

This afternoon's offering is Jack Sock against Marin Cilic - both players' second match of the ATP finals. Having both lost their first matches, both players all but need a win to keep their semifinal hopes alive.

Marin Cilic, the world number five from Croatia, is making his third appearance at the season finale. The former US Open champion is just 1-6 at the event, and is 0-2 against his opponent today. Cilic has just the one title this year, a 250 event in Istanbul, but hit the headlines in the summer by reaching his first Wimbledon final.

Jack Sock is this year's surprise qualifier, having jumped into the top ten in the last week of the season with his first Masters title in Paris. Sock was the first non-European Masters champion since Andy Roddick. Having had more success on the doubles court for most of his career, Sock has three titles in 2017 - two 250 events in the winter to go with the Paris trophy.

So who's the favourite today? Good question. The rankings and career records would suggest Cilic, but Sock leads 2-0 in the head to head. Both of those wins came on big stages - once in the Davis Cup, and once in the US Open. Sock's big serve and huge forehand should be a major advantage on a fast indoor court today.

Players are arriving on court now, with a nice dramatic entrance. No other tournament plasters players' names quite so excitedly over the whole stadium.

Jack Sock had to cancel a golf trip with John Isner to play here apparently. He didn't even expect himself to qualify...

"A must win match" the pundits describe this as. Sounds a little odd to say that in tennis, this is the only tournament where players can lose a match and still take the title, but there we go. Cilic to serve first.

Woah. 100mph return winner on the second point from Sock. That'll send a message. Cilic nets and it's 30-all, and goes wide to give Sock his first break point...

Cilic goes back behind Sock to hit a winner and save it. Deuce. Cilic nets a low Sock passing shot for another break point...and nets again! Sock with the early break.