Boulter forgets new tiebreak rule in Melbourne

If it's taking you some time to get used to the fact that all four Grand Slams now have different rules surrounding final-set tiebreaks, you're not alone.

Great Britain's Katie Boulter, upon taking a 7-4 lead in the third-set buster of her Australian Open debut, started pumping her arms as though she'd already won:

The catch, though, was that, while the Australian Open did institute tiebreaks for final sets this year, the winner is the first one to 10 (winning by two).

The rule differs from the US Open and WTA Tour, which have tiebreaks to seven; Wimbledon, which will use regular tiebreaks but only once the score reaches 12-12; and Roland Garros, which uses no deciding-set tiebreaks at all.

Boulter later got the last few necessary points, winning the tiebreaker 10-6 and the match 6-0, 4-6, 7-6 (6), against Ekaterina Makarova. It marks her second career Grand Slam victory and her Australian Open debut.

This was the first instance of the new rule being used in the main draw.

In the second round, Boulter will take on Aryna Sabalenka, who's already made waves this year by winning the Shenzhen Open.