Juan Martin del Potro has crashed out in the second round of the Miami Masters with a straight-sets defeat to world number 89 Tobias Kamke.
The Argentine fifth seed looked out of sorts on court as he was beaten 7-6 6-1 by his German opponent.
Del Potro came into the tournament on the back of losing Sunday's final at Indian Wells to Rafael Nadal.
Kamke will now face Austrian Jurgen Melzer for a place in the fourth round.
