Lukaku, De Bruyne and Muamba lead Mertens tributes

The death of the Sporting Lokeren defender on Thursday - three days after he collapsed during a match - left many clubs and players grieving.

Figures from across the world of football gave their Twitter condolences to Gregory Mertens after the Sporting Lokeren player passed away on Thursday.

The 24-year-old suffered a cardiac arrest in Monday's reserve fixture with KRC Genk and, after being resuscitated on the pitch, was in a medically-induced coma for days until his death was announced.

Former Bolton Wanderers player Fabrice Muamba was 23 when he went through the exact same situation in March 2012 against Tottenham, except he survived the cardiac arrest, and he passed on his respects.

 Muamba's former club Arsenal passed a message of support to its 5.71 million followers following the central defender's death.

 Closer to home club-wise, Belgian heavyweights Anderlecht tweeted a tasteful photo of Mertens.

 Mertens, who died aged 24, might not have been a household name, but the tragic circumstances of a death suffered while playing the game he and so many others love struck a chord with many players, Fiorentina defender Micah Richards among those.

Premier League leaders Chelsea, the home of Belgian goalkeeper Thibaut Courtois and playmaker Eden Hazard, also paid tribute to Mertens.

 Mertens never featured Belgium's senior team, the centre-back played for the country's youth teams up until Under-21 level and the official account of his home nation's FA also paid their respects

 Manchester City are familiar with heart-related football tragedy due to Marc-Vivien Foe's death in 2003 while playing for Cameroon, which resulted in his final club paying their respects by retiring the No.23 shirt.

Thousands of Belgians poured out support for Mertens and his family after the news broke he had died, and national team stars Romelu Lukaku, Thibaut Courtois and Kevin De Bruyne were among those