NEW YORK, NY, USA - Top seeds Barbora Krejcikova and Katerina Siniakova are two wins away from a third straight Grand Slam title, rallying from match point down to defeat Western & Southern Open finalists Elise Mertens and Demi Schuurs, 2-6, 7-6(7), 6-3 at the US Open.

"We were just thinking, 'Play and fight,'" Krejcikova said of the match. "We weren't playing our best tennis, so it was just important to stay with them, fight for every single ball. When they had a match point, it was a really tough situation but we handled that, won the tie-break."

Krejcikova and Siniakova captured back-to-back major victories at Roland Garros and Wimbledon, and were the first players to qualify for the BNP Paribas WTA Finals Singapore presented by SC Global. They extended their Grand Slam-match winning streak to 16 in a row on Wednesday evening, surviving on Grandstand court after two hours and 21 minutes on court.

Mertens has enjoyed a breakout season in both singles and doubles, not only reaching the second week in three out of the four majors - including the Australian Open semifinals - but also shining on court with Schuurs, winning the Ricoh Open in 's-Hertogenbosch and reaching two more finals this summer. Schuurs is a fast-rising doubles player in her own right, winning the Coupe Rogers with Ashleigh Barty.

Together, the two got out to a fast start against the Czechs, striking an even seven winners to seven unforced errors to take the first set.

"They're absolutely fine," Siniakova said. "Elise plays more from the back and Demi works well at the net. It's part of their team that they can put in something different to make it work. They're really tough to play because they're really aggressive and good fromt he baseline. In doubles, it's really important to serve and return from the first point, and be as aggressive as you want. We were playing well in the end, and that was good."

Krejcikova and Siniakova appeared on course for a decider when they took a 5-3 lead in the second, but Mertens and Schuurs continued to trouble the top seeds, saving three set points to force a tie-break.

The Czechs took another lead in the ensuing sudden death only to be pegged back to match point. From there, they reversed the momentum once more to level the match and ultimately run away with the final set.

"It's tough when you have a bad day to go through and win the match, but we did it. It's good for us for our self-belief," Krejcikova said.

Things nonethless got dramatic in the last game as Krejcikova crashed into the umpire's chair to track a mishit dropshot from Mertens. Momentarily stunned, all Krejcikova cared about was whether her backhand had landed in; Mertens and Schuurs' Hawkeye challenge proved in vain and the Czechs converted their first match point to advance.

"I didn't sprain anything, no ankle or knee or anything," Krejcikova said. "Everything was fine, so I was like, 'What happened? Was it in? Was it out? What happened?' It was such an important point, 5-3, deuce. We would have been down break point, so I knew we had to make it. I was running to the ball, hit it.

"She was looking at me like, 'Are you ok?' because it looked really bad and all I could say was, 'Was it in?' All I could think was, 'Yes! It was worth it, hitting myself. We played match point, and she served and finished with the volley, so I was so happy. I wasn't feeling it on court. It just happened and now it's going to be news!"

Up next for Krejcikova and Siniakova are Miami Open champions Barty and CoCo Vandeweghe, who beat the two in the final women's doubles match at Crandon Park back in March.

"I'm pretty bruised, pretty sore. I'll do my best to prepare for tomorrow, and that's how it is.

"I'm very unhappy," Krejcikova joked. "I played them there when I was sick, and now I'm playing them here and I'm bruised! It's not a good combination, but I cannot wait. It's going to be a really nice match. It'll be a big stadium, and I think a lot of people are going to come because CoCo is an American, a big star here. It's going to be a nice atmosphere."

Should the Czechs win their third straight major at the US Open - and should current World No.1 Timea Babos fail to reach the final with partner and co-Australian Open champion Kristina Mladenovic - Krejcikova and Siniakova will ascend to the top of the WTA rankings on Monday.

"We're going to go out and try our best, and it's going to be a good match."