Fritz produced a stunning performance to secure a shock 6-3, 7-6 victory over Nadal at the Indian Wells Tennis Garden in California in the United States where Poland’s Iga Świątek defeated Maria Sakkari of Greece 6-4, 6-1 to claim the women’s singles crown.

There were concerns that Fritz would not take to the court after aggravating an ankle problem in the warm-up to the match, the conclusion to this Association of Tennis Professionals Tour (ATP) Masters 1000 event. 

But Fritz reportedly went against the advice of his coaches to play through the pain barrier - and it proved to be the right decision as he achieved the best win of his career.

"I can't even begin to describe how ridiculous it is that I was able to play how I could play today," said Fritz.

"I've never experienced worse pain in my life before a match.

"We did a lot of work leading up to the match and I went through a roller coaster of emotions before the match, from thinking there was no way I could possibly play to then doing all this work on the ankle, doing so much stuff to it. 

"I came out here and it didn't really affect me at all."

Nadal had won his opening 20 games of the season, securing three titles, including the Australian Open for a record 21st Grand Slam. 

He was heavy favourite to add to that record but found himself 4-0 behind as Fritz got off to a flying start.

Fritz took the opening start in impressive fashion as Nadal appeared to be struggling.

After taking a medical timeout, Nadal stepped up his aggression and went toe-to-toe with Fritz.

The American failed to convert several break-point opportunities but kept his composure to win the tie-break 7-5 to secure the title.

He became the first the man from his country to win the Indian Wells Masters since Andre Agassi in 2001.

"Winning this tournament especially, Indian Wells, this is one of those childhood dreams that you just never think can come true," said Fritz.

"I just keep saying, 'No, no. Just no way it's real'."

Nadal admitted that he struggled with breathing difficulties during the match which saw him make 34 unforced errors.

"It's tough for me to breathe," said Nadal.

"When I try to breathe, it's painful and it's very uncomfortable.

"When I'm breathing, when I'm moving it's like a needle all the time inside here.

"I get dizzy a little bit because it's painful.

"It's a kind of pain that limits me a lot.

"It's not only about pain, I don't feel very well because it affects my breathing."

In the women’s singles final of this Women's Tennis Association (WTA) 1000 event, Świątek lost just five games in her victory over Sakkari as she earned her second successive title.

Świątek won 14 of the 16 points on Sakkari’s second serve in the first set as she took control of the contest.

The Pole held firm when faced with break points in the second set before seeing off Sakkari in windy conditions.

Her 11th straight victory will see the 2020 French Open champion move to a new career-high position of world number two behind Australia's Ashleigh Barty, who missed this tournament. 

"[The world number two ranking is] pretty surreal for now," said Świątek.  

"I have to look at it and I have to check the rankings by myself and just see it.

"Right now it's too surreal to describe it, honestly.

"But for sure I want to go higher because I feel like getting number one is closer and closer."

Attention now turns to the Miami Open, which is due to start tomorrow and is also an ATP Masters 1000 and WTA 1000 event.