With Novak Djokovic, Andy Murray and Stanislas Wawrinka all absent from this year's ATP World Tour Finals, tournament organisers would have been hoping that Rafael Nadal could deal with an ongoing knee injury to complete the tournament at London's O2 Arena. However, on Monday night, Nadal announced that he would play no further part at the end-of-season event after visibly struggling during his three-set defeat to David Goffin, and it leaves Roger Federer as the clear favourite to add a seventh title to his collection. The Swiss has already recorded a win over Jack Sock, but that is not to say that other players cannot benefit from the absence of Nadal.

The tennis betting odds will naturally have Federer as the clear favourite in any match he competes in from now until the end of the tournament, so unless you fancy the legendary Swiss to drop sets, it makes more sense to stay clear of the 36-year-old's matches. Instead, keep your attentions on the Pete Sampras Group, where two of Goffin, Grigor Dimitrov, Dominic Thiem and Pablo Carreno-Busta are going to get a shot at reaching Sunday's final.

Wednesday's opening match sees Dimitrov and Goffin do battle after their exhausting three-set triumphs on Monday. Dimitrov was largely in control during his victory over Thiem but as we have witnessed in the past, the Bulgarian can be somewhat unpredictable. The pair have already met on three occasions during 2017 and we have had every result aside from a straight-sets win for Goffin. That is available at betting odds of 16/5 if you are feeling ambitious but the 13/10 for a three-set match and Evens for any set to go to a tie-break appear to be the way to go.

The evening session features Thiem versus debutant Carreno-Busta, who is playing in his first-ever match at this event. The 26-year-old's betting odds of 5/2 reflect his lack of experience on this stage, but the US Open semi-finalist has also failed to beat Thiem in any of their four previous matches. That said, three of the contests have taken place on clay, and Thiem needed four sets to get the job done at Flushing Meadows in 2016. There is no doubting that Thiem deserves his status as favourite but the Austrian has won just one of his four encounters on this court, with his sole success coming in three sets against Gael Monfils. There is value in 10/11 for a 2-0 win for the fourth seed, but the value is in a Thiem three-set win at 14/5.

Nadal's withdrawal has also dramatically changed the betting odds for the title. Federer is now as short as 4/9, with Dimitrov being promoted to second favourite at 5/1 due to being tipped to win the Pete Sampras Group. Alexander Zverev is worth a nibble at 6/1, with the most likely final still a meeting between Federer and the talented German, but you may as well bide your time before making a final decision on the third seed. Thiem can be selected at 25/1 to win the tournament and Evens to reach the last four - both are worth a small bet - while a fresh Carreno-Busta is 6/1 to just reach the semi-finals. Given that his opponents are Thiem and Dimitrov, who have both already played three sets, it is worth taking a chance on the newcomer.