A second-set Dan Evans fightback was in vain as the British number three went down to Russia's Roman Safiullin in his Indian Wells Masters opener.
The world number 45 had already defeated Safiullin earlier in the season, triumphing in two sets in their Los Cabos encounter, but the Russian avenged that loss with a 6-1 5-7 6-2 win in one hour and 56 minutes.
Only three places separated the duo in the ATP rankings heading into their Indian Wells encounter, but early mistakes from Evans allowed Safiullin to build up an insurmountable 5-0 lead in the opening set.
The 33-year-old Brit only just avoided a bagel and lost serve in the third game of the second set, but he responded straight away and emphatically, breaking Safiullin to love to get back on level terms before capitalising on a pair of unforced errors from Safiullin while the Russian served to stay in the set.
As was the case in the second set, Safiullin broke for a 2-1 lead in the decider, but while Evans brought up one chance to reply instantly, the world number 42 held his nerve and fired three straight winners to build up a two-game advantage.
The writing was on the wall for Evans when he lost serve once again in the seventh game, and Safiullin closed out the contest in exceptional style, posting a final love hold with three consecutive aces to set up a second-round meeting with Sebastian Korda.
It was not all bad news for the Brits on Thursday, though, as prior to Evans's defeat, Emma Raducanu - awarded a wild card into the Masters event - eased past Spanish qualifier Rebeka Masarova 6-2 6-3.
