It's semi-final day at the ATP Tour Finals and with the big names topping the two groups, our tennis columnist Dan Weston is back with his views on whether either will be beaten today...
'Indoors this year, there really is little comparison between the two players, statistically. Federer has won 70.8% of service points, as well as 41.5% on return. This combines to 112.3%, a figure which is without doubt elite level, and in addition, is a figure far in excess of what the German can boast."
Djokovic and Zverev straight back into action
Following straight-set victories for Alexander Zverev and Novak Djokovic yesterday in London, the duo qualified for today's semi-finals, with the unbeaten Djokovic winning the group and facing Kevin Anderson this evening. Second-place Zverev faces Hewitt Group winner Roger Federer, in today's opening semi-final.
Prior to discussing the two matches individually, it's worth noting that both Federer and Anderson have had an extra rest day, although neither of their opponents today had a particularly arduous final group match yesterday, both concluding their matches in around an hour and a half
Federer with a big statistical advantage over Zverev
Not before 14:00 UK time, Federer faces Zverev, and the Exchange market has the Swiss man priced accurately at [1.41] to make the final - a price my model agreed with entirely.
Indoors this year, there really is little comparison between the two players, statistically. Federer has won 70.8% of service points, as well as 41.5% on return. This combines to 112.3%, a figure which is without doubt elite level, and in addition, is a figure far in excess of what the German can boast.
Zverev is down at 103.0% (63.4% service points won, 39.6% on return) - a combined figure which isn't really even top 10 level - and with this large ability gap on the surface demonstrated by these numbers, it is obvious that Federer should be a solid favourite for this clash.
Zverev historically unable to assert pressure on Federer's serve
Previously, they've met five times competitively, with Federer winning three clashes, although only once indoors - a three set win for Federer at this tournament last year, in the group stages. Federer was just [1.25] that day, and as has been commonplace when priced at around this mark indoors, he covered the game handicap.
Overall, in their head to head meetings, Zverev hasn't been able to trouble Federer unduly on serve, winning fewer than 30% of return points, and he'll need to address this issue today if he is going to progress to Sunday's final.
Djokovic accurately priced as a heavy favourite
Whoever does win this semi-final will be highly likely to face Novak Djokovic. The world number one didn't even drop a set in the group stages, and is [1.15] to get the better of Kevin Anderson in the night match.
Again, my model largely agreed with this market line - I priced Djokovic at [1.18] - and he's had plenty of joy against the South African in the past. In their main tour head to head meetings, he's 7-1 up, having won his last seven.
Anderson with no previous impact on the Djokovic serve
A glance at their head to head data gives plenty of insight as to why Anderson has struggled. In these, Djokovic has held serve on around 96% of occasions, illustrating that Anderson's relatively limited return game has had little impact on the Serb's serve, historically. In addition, Anderson's decent serve has been negated by Djokovic's quality return game, with the big-server only able to hold around 75% of the time in these head to head matches.
Three of Anderson's four set wins over Djokovic have been via tiebreaks, and it seems logical to assume that if Anderson is to cause a shock, this will be the the route he will need to go down. Having said this, I do expect Djokovic to have a fairly routine victory, and to take his place in Sunday's final - a match where he will again be a strong favourite to win.