Wimbledon champions. US Open champions. Nine titles. 55-7 record.

The doubles partnership between Sania Mirza and Martina Hingis is so seamlessly perfect it makes you wonder why it took so long for the two to find each other. Having partnered with deft Cara Black with success last year, Mirza was in search of another crafty net player to balance her baseline strengths. Hingis spent 2014 partnering with both Sabine Lisicki and Flavia Pennetta, both strong baseliners, but needed someone who was willing to focus on doubles.

“Sania has one of world’s best forehands,” Hingis said. “Whether singles or doubles, I think there are not many forehands like her who can hit the ball so hard like her and set me up.”

With Mirza’s forehand cannon patrolling the baseline and Hingis’ IQ at the net, the two won their first two tournaments at the BNP Paribas Open and Miami Open without dropping a set. After winning their first three tournaments together, Hingis and Mirza went on to win their first major together at Wimbledon. It was Mirza’s first women’s doubles title at a Slam and the first for Hingis since 2002. They would finish the season on a 22-match win streak, sweeping titles from the US Open through the BNP Paribas WTA Finals Singapore presented by SC Global. In all, Hingis and Mirza won nine titles and their partnership propelled Mirza to No.1 in the doubles rankings, the first Indian woman to hold the top spot.

When Hingis and Mirza announced they would play Indian Wells together, the biggest question was whether their personalities would mesh. Could the tramlines accommodate two ambitious players of such iconic status? The answer was 100% yes.

“I think it’s fair to say we’ve known each other for fairly long, but fair to say we weren’t probably friends,” Mirza said. “We were people who played against each other and we knew each other, respected each other. Out of that respect came friendship, and out of that friendship obviously came the results. There are so many things that went hand in hand. Of course today I can say that we’re probably very close off the court as well.

“But I think in a lot of the tough moments, that chemistry takes you through, that trust that we have in each other off the court as well. For me, the opportunity to play with her, and the same for her, for both of us, we just feel like we complement each other great on the court.

“When you complement each other off the court as well, I think that’s when you make a deadly combination. I truly believe that a lot of the time we trust each other and go through a lot of tough times.”

And there were tough times on the court. Playing against Ekaterina Makarova and Elena Vesnina in the Wimbledon final, Mirza and Hingis found themselves on the brink of defeat, down 5-2 in the third set. Somehow, in the midst of the nerves and the raucous crowd, they found their best tennis and reeled off five straight games to win, 5-7, 7-6(4) 7-5. To win Charleston they had to come through three consecutive match tie-breaks to make the final.

“The confidence grew with every victory, every tournament,” Hingis said. “It just like was bigger and bigger. Especially that Wimbledon title, because I like playing on grass and the way we played. After that, everything just started clicking together.”

“Obviously the first three months, first three tournaments, we were already like amazing. But I think it’s just… the understanding of each other grew even more. We were already winning from the beginning, but after that was even more and more.”

More, more, more is right. Doubles can yield surprising results and upsets week to week given its small margin for error, but Hingis and Mirza took just one bad loss all season, an opening round exit at the Porsche Tennis Grand Prix to Petra Martic and Stefanie Vogt. That also happened to be their first loss as a team. They dominated the field throughout the year and any challenges they faced came against the world’s best teams, whether it be Bethanie Mattek-Sands and Lucie Safarova, Caroline Garcia and Katarina Srebotnik, or Timea Babos and Kristina Mladenovic.

Said Mirza: “We believe we’re the best team out there and the two best tennis players on the doubles court. I think half the battle is won there.”