Former Swansea City striker Michu scored twice in his first professional game for nearly two years on Thursday, but was unable to prevent Real Oviedo from going out of the Copa del Rey to Murcia.
Michu, 30, who had stopped playing because of the pain caused by ankle problems, joined Oviedo on a one-year contract last month.
He played 120 minutes as Real Oviedo were beaten 4-3 after extra time.
Oviedo's coach, the former Real Madrid and Spain defender Fernando Hierro, told the club's official website: "I am very pleased about Michu's goals -- that will give him a lot of confidence.
Speaking before the game, Michu had told Marca: "I feel very good.
"I live with the pain in my ankle, and that allows me to compete at a good level. What had been most difficult for me was to accept that the pain would never go away."
Michu scored 18 Premier League goals for Swansea in the 2012-13 campaign, but after a lengthy injury layoff and several ankle operations, he rescinded his contract in December.
The striker joined Spanish amateur side Union Popular Langreo early this year before moving to Oviedo. "This is the happiest day of my career," he said at his unveiling last month.