Lokeren's Mertens 'critical' after collapsing on pitch

The match against Genk was 15 minutes old when Mertens collapsed. Belgian media said he had suffered cardiac arrest and received CPR on the pitch, leading to the match being abandoned.

"Our defender was immediately assisted by the medical team of Sporting Lokeren and KRC Genk," a statement read.

"He was transferred to the hospital in Genk.

"Sporting Lokeren sympathises with the family and hopes for a positive outcome."

Club doctor Kris Peeters was quoted by website Nieuwsblad.be as saying the 24-year-old Mertens was in a critical condition.

"Everything points to a cardiac arrest," Peeters said.

"I am in constant communication with the treating physicians in Genk. The state of Gregory is still critical."

Chelsea's Belgium international goalkeeper Thibaut Courtois offered his support on Twitter, along with other players.

"Keep fighting Gregory," Courtois said.

Mertens, 24, joined Lokeren last summer from Cercle Brugge for whom he made nearly 100 appearances.

(Reporting by Martyn Herman; editing by Sudipto Ganguly)