The pairing have had a brilliant year with them going on a 10-0 streak back in March claiming Indian Wells and Miami, back to back.
But after reaching the Roland Garros semi-finals and Wimbledon Quarter-Finals, the doubts would have been there that they could claim one of the main titles on the calendar.
They delivered though seeing off the experienced duo in one hour and 36 minutes of tennis in a tense tie with Azarenka and Barty. They had more winners and fewer unforced errors than the winning duo.
Mertens and Sabalenka though were better on break points and it was the real difference between the pair. They had brilliant few weeks at Flushing Meadows.
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