ATP Tour Finals Day Four: Nadal and Medvedev face each other in must-win clash

Round two of the Agassi group at the ATP Tour Finals is the focus on Wednesday, and with Rafa Nadal fighting for his tournament, our tennis columnist, Dan Weston, gives his thoughts...

Federer and Thiem with Tuesday victories

Tuesday's action in London saw Roger Federer get his campaign back on track with a straight-set win over Matteo Berrettini, but there was a shock in the night match with Novak Djokovic edged out by Dominic Thiem in a topsy-turvy encounter which saw both players blow strong positions in the final set, as well as Thiem needing considerable break point over-perfomance to emerge victorious.

It will be interesting to see whether the market will over-rate Thiem for the rest of the tournament, not taking into account that he needed to save six of nine break point chances and convert four from four in order to win.

However, yesterday's results sets it up superbly for Thursday's action with Thiem already qualified with a match to spare - I wonder what price you could have got on that happening before the tournament - with Federer and Djokovic needing to fight it out for the final qualification spot in a real box-office encounter. I'll be discussing that match in detail tomorrow.

Nadal with fitness to prove ahead of Medvedev clash

Rafa Nadal is in the same boat today as Federer was yesterday - he needs to win in order to avoid elimination. As I mentioned in Tuesday's preview, Nadal's service numbers against Alexander Zverev on Monday were terrible and give weight to the argument of those who consider that he's not close to full fitness.

Simply based on year-long numbers, though, Nadal looks value at 2.24 for his match versus Daniil Medvedev this afternoon. Even with a standard injury adjustment, he'd still look slight value as well. However, I'm not sure we can even look at a standard injury adjustment here with both Nadal's quotes and his service numbers on Monday giving no real cause for optimism.

Now, if Nadal was serving much better and around his year-long numbers (79% first serve service points won, 59% second serve points won, 71% combined) but was either losing or level midway through set one, taking him at an odds-against price can be considered as a potential value spot. However, we have no idea in advance if this is going to be the case and from a pre-match point of view, this looks like an easy leave-alone.

Tight match anticipated between Tsitsipas and Zverev

The second match today is also tricky to analyse with Alexander Zverev having a marginal market edge over Stefanos Tsitsipas, with the Exchange offering 1.89 about the German currently.

This is difficult because hold/break numbers this year make this about right, but service/return points won figures make Tsitsipas a marginal favourite for the win. The Greek man has also won three of their four head-to-head meetings as well, and while this isn't a strong enough sample size to have any real meaning, it's worth noting that Zverev actually has better service/return points won numbers despite having a 1-3 deficit.

For Tsitsipas to have succeeded in these matches between the duo, he has needed to win two out of two tiebreaks, and have absurd break point over performance in some very tight matches. That's usually pretty unsustainable so again, there can be no lean from their previous meetings.

Again, this looks a leave alone to me. If I was forced to take a value pre-match position, it would be Tsitsipas at slight odds against, but given that we have the pre-tournament outright on him, that's enough interest in my view at the current market prices.