Heather Watson was knocked out of the Australian Open by 21st seed Anett Kontaveit as the British challenge in the women's singles came to an end.
It was a gutsy display by the 28-year-old Briton, who battled from 3-0 and 4-1 down and 5-2 down in the tie-break to take the opening set.
The Estonian fought back to take the second set before breaking twice in the decider en route to a 6-7 (5-7) 6-4 6-2 victory for a place in round three.
She will now face USA's Shelby Rogers.
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Watson, ranked 60th, made a sluggish start inside the John Cain Arena against last year's quarter-finalist, whom she had lost to in three of their previous five meetings.
But she soon settled and broke back in the seventh game with a superb cross-court forehand winner before winning five consecutive points to take the first-set tie-break.
A tight second set was effectively decided in the ninth game when Kontaveit's best form came to the fore, producing two great backhand winners to seal her second break.
Watson's own form dipped in the decider. The Briton's win percentage on her first serve had fallen from 71% in the first set to 53% as she was broken twice more with Kontaveit completing her win with another backhand winner.
"I'm disappointed but I'm happy with the way I played," said Watson. "I hung in there - it was such a tough match.
"The momentum was swinging. I managed to fight for everything.
"Anett played really well, particularly serving and returning, which put me under a lot of pressure. Credit to her."
There was British success in the men's doubles on Thursday. Fifth seeds Joe Salisbury and American Rajeev Ram began the defence of their title with a 6-4 6-4 win over Briton Jonny O'Mara and New Zealand's Artem Sitak.
Neal Skupski and brother Ken, the 16th seeds, defeated Canadian singles star Felix Auger-Aliassime and Pole Hubert Hurkacz 6-3 6-2 to reach round two.
Another British pairing, Dom Inglot and Luke Bambridge, came through a match of three tie-breaks to progress to the second round, beating Aljaz Bedene and Jiri Vesely 6-7 (2-7) 7-6 (7-5) 7-6 (10-7).
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