Former world number one Novak Djokovic showed signs of a return to form with an impressive 7-5 6-4 victory over Japan’s Kei Nishikori in the opening round of the Madrid Open on Monday.

Following early exits in Barcelona, Monte Carlo, Miami and Indian Wells, the 30-year-old Djokovic struck his shots with precision and recorded 26 winners to improve his head-to-head advantage to 12-2 against world number 20 Nishikori.

Djokovic was broken to love at 2-2 but he recovered well by pouncing on his opponent’s second serve to clinch the opening set in just over an hour.

The two-time winner in Madrid went on to claim a decisive break in the 10th game of the second set to wrap up the contest.

It was Djokovic’s first victory over a top-20 opponent since the Serb overcame Gael Monfils at Eastbourne in June last year.

Earlier in the day, Canada’s Milos Raonic booked a second-round meeting with third seed Grigor Dimitrov, defeating Argentina’s Nicolas Kicker 6-3 6-2.

Raonic recorded 17 aces to knock out the Madrid debutant.