Ole Gunnar Solskjaer said Manchester United made life hard for themselves with wasteful finishing against Sevilla in the Europa League semi-finals.
A 2-1 defeat in Cologne brought United's season to a disappointing end from their manager's perspective.
He said there were "tired legs, tired minds" on the pitch in the closing stages, after Luuk de Jong poached Sevilla's 78th-minute winner.
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"It's one of them that if you take your chances you win comfortably," Solskjaer told BT Sport.
"But that's not always the case in football.