Doha - World number one doubles pairing Martina Hingis and Sania Mirza lost for the first time in 41 matches, at the Qatar Open on Thursday.
They went down 2-6, 6-4, 10-5 to Russian pair Elena Vesnina and Daria Kasatkina in the quarter-finals.
Prior to the defeat in Doha, the last time the pair, who have won three doubles Grand Slams in a row, had lost was way back in Cincinatti last August.
The all-conquering pair had already shown signs they were struggling this week in Doha, having edged through the previous round in three sets against an unseeded Chinese pairing.
But their luck finally ran out against the Russians despite a dominant first set performance.
Prior to Qatar, their form this year has been magnificent and the Indo-Swiss pairing have already won four titles, including titles in Brisbane and St Petersburg, as well as the Australian Open.
That was their third Grand Slam in a row after Wimbledon and the US Open.
The pair are expected to try and make clean sweep of the major titles later this year at the French Open.
Defeat for Hingis and Mirza came just hours after men's world number one Novak Djokovic saw his run of 17 consecutive finals end at nearby Dubai when he quit his quarter-final with an eye infection.