As the sun burst through the clouds on an otherwise gloomy day at the Madrid Open, there was a stream of light shining on Novak Djokovic as he secured what could prove to be a pivotal win in his season against Kei Nishikori.

Times have been tough for the former world No. 1 in recent months but there were signs of real quality during an absorbing encounter with a high-calibre opponent.

Having avoided Rafael Nadal, Juan Martin del Potro and Dominic Thiem in his half of the draw, there was a sense that this could be a big week for the two-time champion. That was, until Nishikori’s name came out of the hat.

However, with semi-finals points to defend, Djokovic made a statement that he’s still capable of big-match wins as he booked his spot in the second round with a 7-5 6-4 success after two hours.

That’s not to say it was perfect, by any stretch. But there was renewed focus on the biggest points for the 12-time Grand Slam champion and warning signs for the other players in the bottom half of the draw that one of tennis’ true greats is ready to fight like the Djokovic of old. He even threw in a horrendous Djokosmash for good measure!

The Serb entered the match with a healthy 11-2 lead over the Japanese in their head-to-head, and had won 10 straight matches since losing to him in the semi-finals of the 2014 US Open.

However, Djokovic was hardly entering the match at the peak of his powers. The 30-year-old had won as many matches as he’d lost in 2018, most recently suffering a first-round loss to Martin Klizan in Barcelona, as he continues to try and rediscover his best form after a long-term elbow problem.

Nishikori’s condition was also something of an unknown. After reaching the final in Monte-Carlo, where he lost to the all-conquering Rafael Nadal, he withdrew in Barcelona with a wrist injury.

However, he was passed fit to compete at the Caja Magica in a box office first-round tie.

The pair gave a taste of what was to come as the first two games, full of baseline slogging, lasted 11 minutes. Djokovic was forced to save two break points before forcing Nishikori to deuce, but both men held firm.

Four consecutive breaks of serve followed, but on the 40-minute mark the Serb recovered from 15-40 down to get his nose back in front.

Nishikori denied Djokovic on two set points at 4-5 down but could not stop him at the third time of asking at 5-6 and the world No. 12 moved one set up.

For old time’s sake, Djokovic missed the easiest of smashes midway through the second set, though it ultimately caused no him major problems as he broke at the death to secure a huge win.

Britain’s Kyle Edmund may well be his second-round opponent. The world No. 22 will take on Russia’s Daniil Medvedev on Tuesday for the chance to face Serb.