By Matthew Cooper Four-time world champion Mark Selby has admitted he “won’t carry on playing” snooker if his “pathetic” form continues. Selby suffered a 10-8 defeat to Gary Wilson in the first round of the Tour Championship and said he will walk away from the sport if he struggles at this year’s World Championship, which is due to start later this month. The 40-year-old was a finalist at last year’s World Championship, where he was beaten 18-15 by Luca Brecel, but he has struggled for form this year. Speaking after his loss to Wilson, Selby said: “I battled but it was terrible. “If I carry on…