Doubles Take: '21's most prolific title winners in Slam hunt

WATCH: Katerina Siniakova and Barbora Krejcikova win the Roland Garros doubles title.

Throughout the year, no other pairing has won as much as Nikola Mektic and Mate Pavic. The Croatians, playing together for the first time in 2021, have won seven titles on every surface and at every level—except at the majors. Their French Open campaign stopped before it even got started, but they rebounded well during the grass-court stretch, winning in Eastbourne and carrying that momentum with them to Wimbledon. They had to battle to the brink in the quarterfinals against 2017 champions Lukasz Kubot and Marcelo Melo, but now are one match away from a first major final together.

To get to the championship match, they'll have to stop Rajeev Ram and Joe Salisbury, the 2020 Aussie Open champions. Seeded sixth, the American-English duo just stopped the defending champions, Juan Sebastian Cabal and Robert Farah, in the quarterfinals. The other semifinal features the fourth seeds Horacio Zeballos and Marcel Granollers taking on the team of Simone Bolelli and Maximo Gonzalez. Though they're unseeded, Bolelli and Gonzalez have had a strong 2021, including their third win of the season—and first on grass—right before Wimbledon in Mallorca.

On the women's side, Katerina Siniakova and Barbora Krejcikova are out of the running for another French Open-Wimbledon sweep as they fell 9-7 in the third set of their quarterfinal match to Veronika Kudermetova and the veteran, Elena Vesnina. An unseeded finalist is guaranteed as the Russians will next face Caroline Dolehide and Storm Sanders.

The bottom half of the draw features one of the more intriguing matchups of the tournament. Su-Wei Hsieh and Elise Mertens, former world number ones who just started playing together, face arguably 2021's top team, Shuko Aoyama and Ena Shibahara. The Japanese duo has won four titles this year, including their first on grass in Eastbourne right before Wimbledon, and is in the midst of their best Slam run together—one they hope to extend for two more matches.