Britain’s Emma Raducanu showed quality and fight to beat world number 10 Emma Navarro in a remarkable Miami Open contest which she ranked as her best victory of the season.

The 22-year-old won 7-6 (8-6) 2-6 7-6 (7-3) to reach the third round of the WTA 1000 tournament for the first time.

A topsy-turvy decider saw Raducanu close to going a double break down before fighting back to serve for the match.

But, after she was broken at 5-4, the British number two regrouped admirably and held her nerve to dominate the final set tie-break.

It was only the third win of Raducanu’s career against a player ranked in the world’s top 10 – and first on a hard court.

Asked where the win ranked among her performances this season, she told Sky Sports: “It’s number one – because Emma is a top-10 opponent and I haven’t beaten one this year.

“The match wasn’t pretty but I had to fight, scrap and be aggressive.”

Questions have regularly been raised about Raducanu’s resilience and the manner of this gutsy victory will quieten many of her doubters.

Now ranked 60th in the world, she matched Navarro in a tight start before her intensity dropped in the second set.

Raducanu received treatment on a foot injury before the deciding set and, when she faced more break points at 3-1 down, it seemed like her American opponent would quickly wrap up victory.

But the 2021 US Open champion clung on to her serve and played more aggressively as Navarro became edgy.

Raducanu won four games in a row to serve for the match at 5-3 – then was broken again after huge errors with a backhand drive into the net and a double fault.

The way in which she reset again – and continued to dominate with quality returning – was impressive.

Raducanu sealed victory with a ripping forehand winner on her second match point, breaking into a beaming smile and clasping the peak of her hat in shock.

“I have no idea how I won that match to be honest,” she added with a laugh in her on-court interview.

“I don’t know what happened – it was a match full of ups and downs and full of momentum. It was unbelievable – we were both fighting so hard.”

Raducanu continues to be without a full-time coach after she ended a short-lived trial with Slovakian Vladimir Platenik earlier this week.

Against Navarro, she had Mark Petchey – a well-known figure in British tennis circles who worked with her as a teenager – offering coaching advice from her box.

Raducanu’s representatives described Petchey as a “familiar face” who was providing “support”.

It is not clear, though, how long the arrangement will go on for.

Petchey, 54, also coached Andy Murray in the early part of the three-time major champion’s professional career, before becoming a prominent television commentator and analyst.

He watched the match against Navarro alongside Raducanu’s team, which consists of long-time ally Jane O’Donoghue and fitness trainer Yutaka Nakamura in Florida.

“I came here with someone and it didn’t work out, but we put in some great work,” said Raducanu.

“I have good friends here with me, who know my game and know me so well – it’s about trusting your gut and trusting your feeling.

“I think that’s how I got through to be honest.”