Dubai Tennis: Hubert Hurkacz makes the most of his chance with career-best win over Kei Nishikori

Polish world No 77 knocks out top seed for his first win over a top-10 player

Hubert Hurkacz celebrates after winning his second round match against Kei Nishikori in Dubai. EPA

It was a sign of how low Hubert Hurkacz's expectations were for the Dubai Duty Free Tennis Championships that he was happy just to be in the main draw.

The world No 77 arrived in the UAE unsure if he would have to play the qualifying tournament in an attempt to land a spot in the 32-man field for the ATP 500 event.

In the end, he gained direct entry to the main draw and the 22-year-old from Poland has certainly taken advantage of the opportunity.

Hurkacz produced the biggest victory of his career on Wednesday when he defeated top seed Kei Nishikori 7-5, 5-7, 6-2 in the second round to reach the quarter-finals.

Hurkacz had never beaten a player ranked in the top 50 in the world, but he played with confidence and resilience to defeat the 2014 US Open runner-up.

"I was trying to fight for every point," he said. "Kei is an unbelievable player. I had to serve good and that gave me some opportunities.

"The match was a little up and down, but I'm very happy with the win today."

A disappointed Nishikori was eager to praise the man who ended his debut tournament in Dubai after just two matches.

"He played good," the world No 6 said. "I didn't play perfect today, but I think he was playing good."

Hurkacz had been struggling for form in recent months. His first-round win on Tuesday, against Frenchman Corentin Moutet, was only his second victory on the ATP Tour since August.

Yet, he showed fine self-belief to turn around the first set, breaking Nishikori twice when he was serving for the set at 5-4 to win 7-5.

The setback looked to inspire Nishikori, who charged into a 4-0 lead in the second set. But from 5-1 down, Hurkacz once again fought back with two service breaks to to level at 5-5.

However, Nishikori then broke Hurkacz for a third time in the set to serve it out and force a decider.

When it appeared Nishikori had gained momentum, it was in fact Hurkacz who stepped up in the final set with breaks in the fourth and eighth games to produce a defining victory.

"I was staying aggressive," Hurkacz said. "So it gave me a lot of confidence. But the second set didn't start the way I wanted. I had to fight to come back. I am happy with the win in three sets."

For Nishikori it was not difficult to pinpoint where things went wrong for him.

"I think just the serve," he said of a match in which he was broken twice in each set.  "I didn't make much first serves when I wanted to. That cost me some important points. But he played well today."

Like many players this week, the blustery conditions around Centre Court proved problematic for Nishikori.

"With this wind and this surface it is not easy," he said. "Of course, I didn't serve well when I wanted to. It happens. With these conditions, it's never easy."

The setback was surprising for Nishikori given he had enjoyed a strong start to the season.

He won the title in Brisbane, reached the quarter-finals of the Australian Open and made the semi-finals in Rotterdam.

As to how he was going to assess the defeat ahead of the first Masters 1000 event in Indian Wells next month, he said: "I will try to find some reason why I lost today.

"It's too early (straight after the match). I try to fix little bit. I mean, I didn't play really bad. I just need to fix something and be ready for Indian Wells."

Hurkcaz will next face fifth seed Stefanos Tsitsipas, who was a 6-1, 6-3 winner against qualifier Egor Gerasimov in his second-round match.

The two met last week in Marseille, with the Greek winning that encounter in straight sets.