Defending champion Graeme McDowell finished last of the players who made the cut after crashing to a final round of 11-over 82 at the Andalucia Masters.
The former US Open champion had made the cut after opening with two rounds of 73 but fell back after posting a 10-over-par 81 at Valderrama on Saturday.
Things got worse for McDowell on Sunday as he carded six bogeys, a double bogey and a triple bogey to end on 25 under.
Sergio Garcia won on six under, with Shane Lowry fourth on three under.
Former Irish Open champion Lowry carded a final round of 67 to move up the leaderboard.
Miguel Angel Jimenez finished a shot behind his compatriot Garcia on five under, with Richie Ramsay third on four under.
Peter Lawrie ended four over after a 69.
"Hit every tree at Valderrama this weekend and putted awful," said McDowell on Twitter after his final round.
"Took a few risks when out of position and got in worse trouble.
"My swing is elusive for me at the moment - good swings are great but bad ones are out of control. Gotta keep working. I know it's in there.
"Will be a long flight to Shanghai to think about what state my game is in right now.
"But the great thing about golf is I will be level par again on Thursday," added McDowell.