Maria Sharapova today beat Zarina Diyas 6-4 6-4 in the fourth round of Wimbledon 2015, with the Russian still yet to drop at set at the Championships this year.

Yet to be tested properly at Wimbledon 2015, Sharapova today faced a difficult opponent in Diyas, who has already eliminated two seeds in the tournament - Flavia Pennetta in round one and Andreas Petkovic in round three.

Kazakhstan's number one is ranked 34th in the world at the age of 21 and is having a terrific 2015 having at least equaled all her best runs in the three Grand Slams so far this year. However, Sharapova would be encouraged by the fact that she beat the youngster in January at the Australian Open by a 6-1 6-1 scoreline, even if plenty has changed for Diyas since then.

Tight first set edged by shaky Sharapova

The fourth seed got off to a shaky start in the match though, committing two double faults immediately as the game went to deuce. She managed to pull through and hold serve, nonetheless, and set the theme for the first few games in the match for both players with this, as neither served well and both looked nervous on Court Number One.

Sharapova saw a few break points early on, but Diyas defended well as her opponent failed to capitalise on these opportunities. However, the Russian continued to threaten and would break in the fourth game of the match to take a 3-1 lead in the first set courtesy of a fantastic winner at the end of an engaging rally.

Still, Sharapova failed to convince on serve and would be broken right at the end of the set, just as she was serving for it. Having seen two set points as Diyas served to stay in the set herself, the Russian was sloppy and her opponent was determined as she broke back and got the match back on serve at a crucial point. 

However, Diyas then failed to keep her nerve as she served to stay in the set once more, gifting Sharapova three break points and, despite saving the first two, surrendering the set at 6-4.

The Kazakhstan number one was playing good tennis at times, but not when it mattered. She had taken her only break point, but chances when she got 30 on the board on Sharapova's serve were examples of opportunities not capitalised on as the fourth seed took the lead in the match, even though she had been far from convincing thus far.

Diyas can't keep her nerve as Sharapova takes the match

The second set was much more different. Both players started the set with love service games, each player's first of the match, but Diyas would go on to register an early break as Sharapova committed her sixth double fault of the match on a break point to give her opponent a 2-1 lead.

This quickly became 3-1 and was so nearly 4-1 as Diyas came within a point of a double break, but she could not take the chance as Sharapova defended well and held serve to keep within sight of the woman ranked 34th in the world.

Her persistence would pay off too as, in the following game, Diyas gave the Russian a chance to break back and she took it. With the match back on serve, Sharapova then produced a love service game to really assume control of the second set and swing the momentum back in her favour.

Just as with set number one, Diyas would be forced to serve to stay in set number two, but would need to show far more composure this time as she was also serving to stay in the match.

However, she again lacked the ability to do this and allowed Sharapova to see a match point, which the Russian took with sheer power as her opponent could only return the ball into the net.

There are plenty of encouraging signs for Diyas to take from the match, and the tournament in general, and she certainly possesses the potential to have a marvellous career, being just 21-years-old now.

The youngster did not approach the net enough in the match though, and this is a tactic that has worked so well for her at Wimbledon 2015, especially as she defeated Pennetta in round one. If she can improve the weight of certain shots too and simply gain more experience and, in turn, composure, she can go on to become a truly fantastic player in the future.

However, it was Sharapova's day and Sharapova's victory, and now she will aim to maintain her record of reaching the final of Wimbledon every time she reaches the fourth round.

The Russian faces Coco Vandeweghe in quarter-finals after she beat Lucie Safarova, the 2015 French Open finalist, 7-6 7-6 today. The winner of that match is then likely to face the 2015 French Open winner, Serena Williams, in the semi-finals, who beat her sister Venus this afternoon and will play either Victoria Azarenka or Belinda Bencic in the quarter-finals.