Emma Raducanu created history by winning the US Open women's singles final as a qualifier, the first woman to do so in the Open era.

Raducanu's dramatic 6-4, 6-3 victory over Leylah Fernandez was characterised by fast, high-risk tennis of supreme quality, in which both women had chances to assert their will on the contest.

However, it wouldn't be a final at the US Open unless there was some form of controversy, however tenuous and contrived, and this match was no exception.

What happened?

Momentum in grand slam finals can turn on the slightest moment, and there was a pretty big moment in what ended up being the final game.

With Raducanu serving for the match at 5-3, Fernandez suddenly re-discovered her form to earn a break-back point at 30-40.

It came after a brilliant rally featuring some stupendous court coverage from Raducanu, which included some wicked slides that left trails of shoe rubber all over the court — but also opened a cut on her knee.

That resulted in a medical timeout being called, much to the chagrin of Fernandez, who argued the point with the match referee.

Sure, it wasn't an eight-minute-long toilet break-style interruption, but it certainly helped swing momentum back just at the right time in favour of the precocious British teenager.

So, did Fernandez have a point?

What do the rules say?

Let's check section 3.f. of the International Tennis Federation's Grand Slam Rule Book. 

Bleeding

If a player is bleeding, the Chair Umpire must stop play as soon as possible, and the Sports Physiotherapist must be called to the court by the Chair Umpire for evaluation and treatment. The Sports Physiotherapist, in conjunction with the Tournament Doctor if appropriate, will evaluate the source of the bleeding, and will request a Medical Time-Out for treatment if necessary.

If requested by the Sports Physiotherapist and/or Tournament Doctor, the Referee in consultation with the Grand Slam Supervisor or Chair Umpire may allow up to a total of five (5) minutes to assure control of the bleeding.

If blood has spilled onto the court or its immediate vicinity, play must not resume until the blood spill has been cleaned appropriately.

Seems pretty clear cut, if you excuse the pun.

Blood was visibly trickling down the front of Raducanu's shin, meaning that the chair umpire, Marijana Veljović, had no choice but to stop play.

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Fernandez did appear to be upset at the amount of time the treatment was taking, which is very understandable given the game situation.

However, the medical staff were going through their process and Raducanu bounced up off her chair before the time had expired for the time out.

What did Raducanu say?

When asked about that moment, the new US Open champion said she was just hoping to maintain her composure.

"I fell somehow, and I thought that would throw myself off somehow because I had to serve," she said.

"Just staying in the moment really helped."

What did Fernandez say?

"I honestly did not know what was happening with Emma," Fernandez said in the post-match press conference.

"I didn't know how serious her fall was, so that's why I went to see the official and ask her about it.

"It was just too bad that it happened in that specific moment with me with the momentum. But it's sports, it's tennis. Just got to move on."