Wimbledon 2017: Key clashes to watch out on Day 4

1) Rested Federer in the groove

After spending just 43 minutes on Centre Court before the injured Alexandr Dolgopolov pulled out of their first round clash, Roger Federer returns to action against Serbian world number 79 Dusan Lajovic.

Federer, bidding to win Wimbledon for a record eighth time, was in fine fettle against Dolgopolov, racing into a 6-3, 3-0 lead before the unexpectedly early finish.

A withdrawal wasn't the most satisfying way to secure a record 85th match win at Wimbledon, but the 35-year-old, who hopes to become the tournament's oldest male champion, will have enjoyed the extra rest before his first ever meeting with Lajovic.

Head to head: First meeting              

2) Kerber eyes revival

World number one Angelique Kerber takes on Belgium's Kirsten Flipkens as she looks to build on an encouraging straight sets victory over US qualifier Irina Falconi in the first round.

Kerber was beaten by Serena Williams in the Wimbledon final last year and, with the US star absent, she is among the favourites to make it back to the title match despite a rocky run in 2017.

If the German, winner of the Australian and US Opens last year, is looking for good omens, she came from a set down to knock Flipkens out of Wimbledon in their last meeting three years ago.

Head to head: Kerber leads 2-0              

3) First test for Djokovic          

Three-time champion Novak Djokovic is first up on Court One against Adam Pavlasek of the Czech Republic in what will be his first proper test at Wimbledon this year.

The Serbian second seed was leading 6-3, 2-0 against Martin Klizan when the Slovak retired after just 40 minutes on Centre Court on Tuesday.

However, it was the kind of trouble-free first round Djokovic would have been hoping for after the most turbulent period of his career, the 12-time major winner losing in the Australian Open second round and the French Open quarter-finals.

Head-to-head: First meeting            

4) Del Potro, Gulbis in duel of struggling stars

2009 US Open champion Juan Martin del Potro faces Ernests Gulbis in a battle of the two of the sport's great unfulfilled talents. Del Potro was pushed to the brink of retirement last year after three wrist surgeries but surged back to help Argentina win a maiden Davis Cup title.

Del Potro was a semi-finalist in 2013. Gulbis made the top 10 in 2014 in the year he made the French Open semi-finals, beating Federer on the way. The Latvian's opening round win was his first on tour in 13 months, a slump which has seen his ranking sink to 589.

Head-to-head: Del Potro leads 4-2             

5) Pliskova v comeback queen Rybarikova

Karolina Pliskova is one of the favourites for the title in the absence of Serena Williams and following the defeat of Petra Kvitova. The tall Czech is bidding to make the third round for the first time.

Thursday's opponent Magdalena Rybarikova, a former world number 31, missed seven months after undergoing knee and wrist injuries which saw her ranking slip to 453. But she came into Wimbledon with two titles on grass at Surbiton and Ilkley.

Head-to-head: First meeting