Jamie Murray and Bruno Soares lost in the Japan Open doubles final to home pairing Ben Mclachlan and Yasutaka Uchiyama in Tokyo.
The wildcard entries beat the second seeds 6-4 7-6 (7-1) for their first ATP World Tour team title.
The surprise winners had overcome number one seeds Jean-Julien Rojer and Horia Tecau in the quarter-finals.
Murray and Soares, fourth in the ATP Doubles Race To London, were aiming for a fifth title of the season.
The defeat means the Scottish-Brazilian partnership have won four and lost three finals this year, while Murray also won two Grand Slam mixed doubles titles, at Wimbledon and the US Open, with Martina Hingis.
Murray, 31, now has a career record of won 19, lost 20, in tour-level finals.
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