Who is in the hunt for gold in this year's Summer Olympics?

As the Olympic tennis event reaches its closing stages, it's still all to play for in both singles events. Federer, Djokovic, Murray and Tsonga all still in contention for gold in the men's, whilst Williams, Sharapova, Kvitova and Azarenka remain well on course in the women's event. 

Novak DjokovicThere's no question at all what has been the standout match in the men's side of the draw. We, were always expecting a big serving battle when Jo-Wilfried Tsonga met Canadian, Milos Raonic in Round 2, but when Tsonga took the opening set without too much trouble, it looked as if the battle would be over quickly. Raonic thought differently and stormed back to take the second set and go toe-to-toe with Tsonga in the decider. With the final set locked at 21-21, the Wimbledon crowd were wondering if the 70-68 final set record of Isner and Mahut in 2010 may be broken, but the Frenchman finally found a way through, to break the Canadian spirit and book himself a place in the third round. 

The two favourites for gold have gone about their business without too much trouble. 

Novak Djokovic has actually dropped sets to Fognini and Hewitt but never really looked in danger in either match, whilst Roger Federer dropped a set in his opening match with Falla, but has moved through to the last 8 without the loss of any further sets.

Andy Murray is playing in front of his home fans for the second time this summer and is handling the pressure well. Having dropped the opening set to Baghdatis in the third round, Murray held it together and bounced back to defeat the Cypriot for the second time in the last four weeks. 

With Djokovic and Murray looking destined for a semi-final meeting in the bottom half of the draw and Federer needing to get past Isner in the quarters and then probably Del Potro in the semis, it's easy to see why the tennis bookmakers are having a tough time splitting the big two. 

Federer is still the favourite, at 11/8, but at 13/8, there's little to suggest the Serb can't go all the way and win the gold for his nation. Murray may have to beat both men if he wants to win this one and can be backed at 4/1, but there may be more value in the big servers like Tsonga and Isner who are backable at 20/1 and 50/1 respectively.

Meanwhile, over in the women's event, things are looking equally tight. There's no question that Serena is still a big favourite with the bookies and having not dropped a set so far, it's easy to see why. Serena came through her third round match with Zvonareva for the loss of just one game and is looking almost unstoppable as she prepares for a last eight match with Woznicaki. 

Sharapova and Kvitova remain on course for a semi-final showdown, with the winner likely to go on and meet Serena in the final. Whilst Serena can only be backed at tennis odds around 11/10, the 11/2 and 6/1 on Sharapova and Kvitova look a little more tempting. The chances are that one of the two will be playing in the final, and once there, they'd both be capable of causing problems.

Angelique Kerber continues her stunningly consistent season with another quarter final appearance and she has every chance of causing an upset against Azarenka. It would be fascinating to see Kerber go up against Williams in the semis and you certainly wouldn't count her out of at least bringing home a medal for her nation.