MELBOURNE -- Marta Kostyuk survived a late-night thriller at the Australian Open, saving a match point to defeat Elise Mertens 5-7, 6-1, 7-6 [10-6] in the second round. The 21-year-old Ukrainian needed every ounce of energy she had to get past the Belgian veteran, as evidenced by the 42-shot rally she endured late in the final set. 

Looking to make her fourth Australian Open third round, Kostyuk stormed back after dropping a competitive first set to take the match into a decider. The final set spanned 83 minutes, with the average rally length nearing seven shots per rally. 

With Mertens serving with a game point at 4-4, Kostyuk dug in to prolong the game. The duo had played a 31-shot rally just two points before, but with the game on the line, Kostyuk gritted her teeth to outduel Mertens from the baseline.

Watch the grueling point below:

The effort nearly paid off immediately. After getting the game to deuce, Kostyuk earned a break point for a chance to serve out the win, but Mertens wiped it out with an unreturnable serve.

Kostyuk would face match point on her own serve at 5-6, but the match went into a 10-point match tiebreak after Mertens missed a backhand pass. 

In the tiebreak, Kostyuk came back from 3-0 down level at 6-6, before running off the last four points for the win. 

Kostyuk will face Elina Avanesyan next. The Ukrainian is bidding to make her first Grand Slam Round of 16 since 2021 Roland Garros.