They were born fewer than five months apart in the Czech Republic and, at least in the beginning, didn’t seem destined to dominate the world of professional tennis as a dynamic duo.

Barbora Krejcikova remembers seeing Katerina Siniakova for the first time at the Czech Championships for 12-under players.

“Long time ago,” Krejcikova said last week from the Guadalajara Open Akron. “I remember her running from side to side very fast. How do you say? Grunting. Run to right, grunt! Run left, grunt! Run right, grunt! Every time.

“I remember also her fighting spirit -- and that the racquet was even bigger than her.”

Road to the WTA Finals: Krejcikova and Siniakova

Five years later, in 2013, they played doubles together for the first time in the junior competition at Roland Garros. The 17-year-olds won the title -- and three of the year’s four majors -- and have grown into the consistently best team on the Hologic WTA Tour.

This year they were the first doubles team to qualify for the WTA Tour Finals in Fort Worth, which begin next Monday.

A year ago, Krejcikova was the first player in five years, since Angelique Kerber, to qualify in both singles and doubles. And while she lost all three of her round-robin matches, she and Siniakova won five, including the final over Hsieh Su-Wei and Mertens.

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This year’s doubles success was based largely on some spectacular play in the majors. In a back-to-the-future turn of events, the Czech mates won all three of the Grand Slam events in which they played, the Australian Open, Wimbledon and the US Open.

“Actually, if somebody would tell me that we would win three Grand Slams,” Siniakova said, “I would say, `My gosh, that would be amazing.’”

And it truly was. The pair won each of their 18 matches in majors. They defeated Anna Danilina and Beatriz Haddad Maia in the Australian Open final after losing a first-set tiebreak. They again dropped only a single set overall at Wimbledon, beating Elise Mertens and Zhang Shuai 6-2, 6-4 in the final. They overcame a one-set deficit to Catherine McNally and Taylor Townsend in the US Open final. Their last three matches in New York went the distance.

And while Krejcikova, the 2021 Roland Garros champion, is the better singles player today -- she was ranked No.17, some 37 spots ahead of Siniakova -- it wasn’t always that way. Four years ago, when the Czechs won Roland Garros and Wimbledon to break through with their first senior-level major titles, Krejcikova wasn’t even ranked among the Top 200 in singles. Even playing five ITF events in 2018, Krejcikova ended the year at No. 203. Siniakova was already a Top 50 player by 2016.

Last season, after two years without a major title, it came back together with titles at Roland Garros, the Tokyo Olympics and the WTA Finals in Guadalajara. That set the table for their rare success in 2022.

In their 10th year of playing together, it makes a certain sense.

“If one of us is doing something, the other one already knows where to move and what to do,” Siniakova said. “We don’t need to say to each other where she’s going to hit because we kind of already know that. So, it’s helping us to already move on the court [earlier] because you know what’s coming.”

They are perfectly complementary players. What does Krejcikova do better?

“I think she plays better the forehand than me,” Siniakova said. “I want to have her forehand.”

What does Siniakova do better?

“I would say, actually, the backhand side,” Siniakova said. “So I would think that maybe she would want my backhand.”

They both wish they had been able to play at Roland Garros for a chance at history. Siniakova, who was nursing an abdominal injury, lost in the second round of singles, while Krejcikova, fighting an aching elbow, lost in the first. When Krejcikova tested positive for COVID-19, they were forced to withdraw from doubles.

“Looking back, it’s really sad,” Siniakova said. “This year so far we had some injury troubles, both of us, but it’s great to see now that we have won three Grand Slams.”