Spain's Pablo Carreno Busta survived a match point to upset sixth seed Kevin Anderson 6-4 5-7 7-6 (8-6) and reach the Miami Open semi-finals.
For Carreno Busta, who arrived on court in fine form having dropped only 12 games over his previous three matches, the win was his first in five meetings against Anderson and avenged his fourth-round Indian Wells loss to the world No.8.
Anderson saved a pair of match points in the second set and shifted momentum in his favour but Carreno Busta, seeded 16th at Crandon Park, regrouped in the decider where the two players stayed on serve until the tiebreak.
Carreno Busta was staring at defeat when 6-5 down in the tiebreak but was let off the hook when Anderson missed with a forehand.
From there the South African pushed a backhand volley wide and then mis-hit a second serve that handed the win to Carreno Busta after two hours, 42 minutes.
Carreno Busta will next face the winner of Thursday's other quarter-final between German fourth seed Alexander Zverev and Croatian 29th seed Borna Coric.
Anderson, whose year already includes an ATP Tour title at the New York Open and runner-up finishes in Acapulco and Pune, has now lost all 10 of his quarter-final matches at the Masters 1000 level - the highest-tiered tournaments after the four grand slams.
