Spanish number one Rafael Nadal began his participation in the Madrid Open tennis tournament with a comfortable straight sets win on Wednesday.

Nadal, who is seeded number two in the competition, won the second round tie against Ukrainian Oleksander Dolgopolov 6-4, 6-3 in a match that lasted just under one and a half hours.

The Spaniard made good use of a powerful and accurate first serve against Dolgopolov, 75 percent of his first serves were in and he only had to defend one break point in the match.

It was the perfect opening game for Nadal, who was struggling with a knee injury at last year's competition. He has also had knee problems at the start of this season and will be happy to have got through with no problems.

Nadal's win gives him a match against American John Isner. The number 13 seed today progressed into the third round thanks to a three set win, 1-6, 7-6 (6), 6-2 against Colombian Sebastian Giraldo.

Isner needed time to find his form and after losing the first step, he was in trouble as the second set went to a tie-break, which he won before finding his form in the final set to clinch the match.

Nadal recently defeated the American in the Masters tournament in Indian Wells.