Angelique Kerber came back from the brink to beat Shelby Rogers in a titanic third-round battle at Wimbledon and keep her hopes of remaining world number one alive.
The runner-up to Serena Williams at the All England Club 12 months ago, Kerber needs to reach the final again to have a chance of holding on to top spot in the rankings.
It appeared the German would not even make Wimbledon's second week when she lost the first set on Saturday and then faced a break point trailing 4-2 in the second.
However, Kerber raised her game in the nick of time to pull level, before coming through a dramatic decider to claim a 4-6 7-6 (7-2) 6-4 victory on No.2 Court. She will now face Garbine Muguruza in a meeting of the tournament's last two losing finalists.
Rogers' confident start belied her world ranking of 70, the American hitting twice as many winners as the top seed in the opening set.
And Kerber's prospects appeared bleak when a wild backhand gave her opponent a deserved early lead in set two.
Yet, after digging deep to remain only one break behind, Kerber came from 30-0 down to pull level at 4-4 - winning the standout point of the match in the process as she followed up some tremendous defensive play with a powerful attempted pass that set up a winner at the net.
With her forehand starting to prove a particularly potent weapon, Kerber duly dominated the second-set tie-break, levelling the match at the second time of asking despite having to delay her serve due to the unwelcome attentions of a wasp.
The sting looked to have been drawn from the contest when Rogers gave up serve to fall 2-0 down in the decider, a succession of unforced errors from the underdog eventually punished as Kerber took her seventh break point of the game.
There was more drama to follow, Rogers producing a comeback of her own and even threatening to move a break up, but the gutsy Kerber ultimately did just enough to overcome an increasingly erratic rival.
Kerber  bt Rogers 4-6 7-6 [7-2] 6-4
Kerber - 25/14
Rogers - 48/47
Kerber - 1/4
Rogers - 6/2
BREAK POINTS WON
Kerber - 3/11
Rogers - 3/8
FIRST SERVE PERCENTAGE
Kerber - 68
Rogers - 59
PERCENTAGE OF POINTS WON ON FIRST/SECOND SERVE
Kerber - 66/51
Rogers - 69/49
Kerber - 110
Rogers - 109