They christened their partnership last spring with 14 straight victories through Indian Wells, Miami, and Charleston. They ended the season undefeated from the US Open through the BNP Paribas WTA Finals Singapore presented by SC Global, bringing that streak into 2016 before the run ended at the Qatar Total Open - with an impressive haul that included nine titles and two Grand Slam trophies.
Co-No.1s since January, they head into the French Open in search of a "Santina Slam" with two active streaks in their arsenal: one at major tournaments (18 straight since Wimbledon), and the four matches in a row to win their most recent title - and first on red clay - at the Internazionali BNL d'Italia.
For all of their winning, red clay was the final frontier for a team who arrived in Rome after finishing second in both Stuttgart and Madrid - losing to the then-streaking French Connection of Caroline Garciaand Kristina Mladenovic each time.
Recovering from a second set hiccup on Sunday, Santina dispatched Ekaterina Makarova and Elena Vesnina, who they beat to kick off their Grand Slam streak at last year's Wimbledon final, 6-1, 6-7(5), 10-3.
The French Open bears extra significance for two women who've experienced bitter disappointment on the terre battue. Mirza was one half of another team to beat back in 2011, when she and Vesnina reached the final at Roland Garros. Her bid to win her first major women's doubles title came to an unexpected halt at the hands of an unseeded Czech duo, Silent H's Andrea Hlavackova and Lucie Hradecka.
Hingis' struggles to peak in Paris are well-documented, and the French Open is the only major tournament where she lacks a box set of singles, doubles, and mixed titles.
None of that may matter a fortnight from now, as Santina seem to have weathered a spring hardcourt slump to rebound on a surface where they've traditionally enjoyed the least success. Earning wins over nearly all of the teams likely to pair up next week, Hingis and Mirza's French nemeses will have the added pressure of playing at home, while defending champions Bethanie Mattek-Sands and Lucie Safarova lost the only match they've played on red clay since winning the Miami Open.
Victory would cement their already legendary partnership with a Non-Calendar Year "Santina Slam." The last team to win four majors in a row was Venus and Serena Williams, whose campaign also started at Wimbledon and ended at the French Open in 2010.
Victory would also mean that the streak goes on. Along with Pam Shriver and Martina Navratilova, Hingis is one of only three women to complete the Calendar Year Grand Slam in women's doubles - albeit with two different partners - in 1998, winning the Australian Open with Mirjana Lucic-Baroni and the final three legs with Jana Novotna. Who would believe that, 18 years later, the Swiss Miss could be in contention for a Golden Slam?
Well before such lofty goals appeared possible, Mirza was quick to pump the breaks and add perspective.
"It's a Grand Slam for a reason, and the reason is that it's so tough to win even one in your lifetime,"Mirza told WTA Insider back in January after she and Hingis had captured the Brisbane International. "If it happened, it would be amazing, but it's not something we're focusing on, to be honest.
"We're just trying to take it one match at a time. Every match is tough; we're just going to go there, focus on one match at a time, and hopefully get into the Slam.
"If we win it, great. If we don't, we move on."