No.2 seeds Storm Hunter and Elise Mertens finished group play at the GNP Seguros WTA Finals Cancun with a perfect 3-0 record after dispatching No.5 seeds Desirae Krawczyk and Demi Schuurs 6-2, 6-3 on Thursday.
Hunter and Mertens's undefeated run through round-robin play means they will finish at the top of the Maya Ka'an Group, and they have qualified for the knockout semifinals this weekend.
Meanwhile, second place in the Maya Ka'an Group is still up for grabs, after No.8 seeds Nicole Melichar-Martinez and Ellen Perez notched their first win of the week with a 4-6, 6-2, [10-6] victory over No.3 seeds Shuko Aoyama and Ena Shibahara earlier on Thursday.
Melichar-Martinez and Perez will secure second place in the group with a win in their final round-robin match on Friday. Otherwise, Aoyama and Shibahara will finish second place in the group. The top two teams in each group advance to the semifinals.
Hunter and Mertens remain flawless in Cancun: Krawczyk and Schuurs defeated Hunter and Mertens in the Montreal semifinals this summer, but Hunter and Mertens avenged that loss on a blustery day in Cancun, prevailing after 1 hour and 13 minutes.
It was a sterling display by the second seeds, who had 18 winners to their opponents' eight. Hunter and Mertens also had a 6-for-9 conversion rate on break points in the clash.
Defending champion Mertens continues her superb run of form at the WTA Finals. She has won her last eight matches at the event, having gone 5-0 last year while paired with Veronika Kudermetova. Mertens also reached the 2021 final alongside Hsieh Su-wei.
Melichar-Martinez and Perez overcome rain delays: As for Melichar-Martinez and Perez, they have seen all of their scheduled matches affected by rain this week, and Thursday's clash was no exception.
However, the American-Australian duo survived one lengthy rain break and another shorter one to capture the win in 1 hour and 32 minutes of play.
On Thursday, the teams got through only two games before rain interrupted the match for nearly two hours. Upon resumption, Aoyama and Shibahara took the first set, where half the games went against serve.
But Melichar-Martinez and Perez turned around the momentum, sweeping through the second set to reach the decisive match-tiebreak.
In the 10-point breaker, which had a three-minute pause for a shower, stellar volleys by Melichar-Martinez and Perez led them to a commanding 6-2 advantage.
The Japanese tandem pulled back into contention by reaching 6-5 in the match-tiebreak. However, Melichar-Martinez and Perez held firm, winning four of the next five points to triumph, exacting revenge for a loss to Aoyama and Shibahara at Indian Wells this year.