Aryna Sabalenka was left confused by the ten-point tiebreak rule during her deciding set against Madison Keys in the US Open semi-final, leading her to celebrate winning the match prematurely.

Second seed Sabalenka has been solid throughout the last Grand Slam of the year in New York. Prior to her semi-final match, the Belarusian had not dropped a set against the likes of Clara Burel, Daria Kasatkina, and Qinwen Zheng.

However, Sabalenka found herself in some trouble during her clash with Keys, losing the first set 0-6 to the American player. Nevertheless, the 25-year-old proved why she is the soon-to-be World No. 1 as she fought back to take the second set on a tiebreak, before doing the same in the third and booking her spot in the final by the skin of her teeth.

Although Sabalenka won the final tiebreak at ten points, the Australian Open champion believed herself to have made it through the match a few points earlier. This is because ordinary tiebreaks are decided by the first to reach seven points, but the deciding set tiebreaker is won by the first player to get to ten.

While tiebreak rules have differed across Slams in the past, this system was put in place across all majors starting last year.

However, after an arduous match, Sabalenka made the easy mistake of thinking the final tiebreak went to seven, meaning that when she won the point to make it 7-3, she dropped her racket and began celebrating her victory. Thankfully, her team quickly reminded her that she still had three points to win, and the Belarusian returned to the match which she won shortly afterward 10-5.

Speaking afterwards, Sabalenka said she was glad that she was able to stay focused and not let the mistake cause the match to slip away from her.

"Oh actually I thought that it’s… That we play tiebreak till upto seven [points]. I don't know. I was just all over the place and I was, I don't know, it was crazy, but thanks team that you reminded me that it actually up to 10.

"I'm really, I'm really happy that after that reaction I was able to stay focused and I was able to finish this much because it could be other way around," she said.

Sabalenka will go on to face sixth seed Coco Gauff in the final of the US Open.