By SABC Sport
17th April 2024
The 37-year-old was playing just his second tournament in 15 months after suffering another hip problem at his comeback event in Brisbane in January.
And having intimated that this will be his final year before retirement, Nadal's defeat was likely to mark his final appearance at a tournament he has won 12 times.
Having overcome Italian Flavio Cobolli in the opening round, Nadal faced a much sterner test against the in-form De Minaur and was sent scampering around the court in a tight opening set which was edged by the Australian.
De Minaur went on to step up a gear, securing a double break over the Spaniard and racing over the line behind a strong service game on which he did not drop a single point in the second set.
Jack Draper made the most of a rain delay to defeat wild card Rudolf Molleker and reach the quarter-finals of the BMW Open in Munich.
German Molleker, ranked 179th, had been the better player in the first set but a brief stoppage ahead of the second set changed the momentum of the contest.
Draper began to assert his powerful game after the resumption and lost only two more games, pulling away to claim a 4-6 6-1 6-1 victory.
In the last eight the British number two, who is ranked 46th, will take on either third seed Taylor Fritz or Spanish qualifier Alejandro Moro Canas.
Speaking in an on-court interview, Draper said: "I think Rudy played an amazing level in the first set.
"The conditions were very rainy and very slow. In the second and third, the sun comes out and I start feeling better. I'm really proud of the way I played."