Novak Djokovic's pursuit of a record seventh Miami Open ATP title ended in dramatic fashion on Tuesday as Roberto Bautista Agut superbly recovered from a first set destruction to win 1-6, 7-5, 6-3 and book a place in the quarter-finals.
And the top seeds kept falling as women's world number two Petra Kvitova slumped to a surprise 7-6 (8/6), 3-6, 6-2 defeat to Australian Ashleigh Barty.
Bautista Agut, 30, may have beaten Djokovic on the way to winning the title in Doha earlier this year but 15-time Grand Slam champion Djokovic started like a train in this last 16 encounter before being amazingly reined back in.
After just 25 minutes, Djokovic was 5-0 ahead and on cruise control, Bautista Agut severely struggling to keep the Serbian at bay.
A short rain delay late in the second set allowed Bautista Agut to regroup, however.
He returned a completely different player and at the end of an absorbing two hours and 29 minutes, it was the number 22 seed who will now meet defending champion John Isner for a place in the semi-finals.
"He is a solid player but I shouldn't have lost this match, I had way too many wasted opportunities," said the world number one, who also failed to make the latter stages of Indian Wells this month.
Big-serving Isner moved into the last eight with a 7-6 (7/5), 7-6 (7/3) triumph over Great Britain's world number 22 Kyle Edmund.
Elsewhere there was a brilliant win for 18 year-old Felix Auger-Aliassime, the Canadian who came through qualifying, who beat Georgia's Nikoloz Basilashvili 7-6 (7-4), 6-4.
Auger-Aliassime, who is set to become the first player born in the 2000s to break into the top 50 when the rankings are updated next week, plays Borna Coric after the Croatian beat Nick Kyrgios 4-6, 6-3, 6-2.
In the women's draw, Barty, who beat Kvitova for the first time having gone into the clash 0-4, will play Anett Kontaveit for a place in Saturday's final after the Estonian brought an end to Hsieh Su-Wei's impressive run with a 3-6, 6-2, 7-5 victory to reach the last four in South Florida for the first time.