Kei Nishikori is through to the second round of Wimbledon with a hard-fought five-set win over Simone Bolelli.

The Japanese star raced out of the blocks and broke his opponent early on his way to winning the first set 6-3.

However, Bolelli, who lost Nishikori at the championships last year, managed to take the second set to a tie-break, which he won 7-4 to level the scores.

Nishikori upped his game in the third set though, as he produced some excellent winners to break Bolelli twice and take a one-set lead again, but the Italian player wasn't put off his stride, as he quickly broke the 25-year-old in the fourth set and held his nerve to take it to a decider.

Nishikori immediately broke Bolelli to wrestle back control again in the fifth but he needed a medical time-out for an injured calf when he was 3-0 up, and that allowed his opponent to get his first game on the board when they resumed.

The fifth game of the set went to the wire as both players squandered chances to win it, until Bolelli sent a forehand long to put the fifth seed 4-1 up.

From there, Nishikori kept his cool and served out the set 6-3 to clinch victory.