Brussels: Belgian footballer Gregory Mertens died on Thursday, just three days after suffering a heart attack while playing for Lokeren's reserves, hospital sources told the Belga news agency.

The 24-year-old defender had been in a critical condition after collapsing on the field 20 minutes into a reserve game against Genk on Monday. He was given emergency treatment on the pitch before being taken to hospital where he was placed in an induced coma.