Ronnie O'Sullivan clawed his way back into contention after a torrid opening session of the World Grand Prix final against Judd Trump in Leicester.The world number one had swept into the final on the back of a dazzling semi-final win over Ding Junhui, but his touch looked to have deserted him as he slumped to a 4-0 deficit by the mid-session interval.But O'Sullivan, looking to build on his recent UK Championship and Masters titles, recovered to narrow the gap to two frames at 5-3 ahead of Sunday evening's resumption in their best-of-19 clash.Despite questioning his future in the sport during much of his run to the final, O'Sullivan conceded he had barely played better than in his last-four win over Ding, when he rifled four centuries to triumph 6-1.But it was Trump who seized the initiative on Sunday with a break of 74 giving him the first frame, before O'Sullivan uncharacteristically spurned a chance to steal the second as he fell two behind.O'Sullivan once again failed to punish his opponent for a pair of misses in the third frame, going in-off during an attempted safety which enabled Trump to chisel out the points required to extend his lead.A nightmare mini-session was complete as Trump made 69 to move further in front, but O'Sullivan finally stirred upon the resumption to take the fifth frame in two visits.Trump failed to punish O'Sullivan for more misses in frame six, but he got the better of frame seven in what was proving an increasingly scrappy encounter to restore his three-frame lead.Trump again spurned a fine chance to wrap up the afternoon session four frames in front when he missed a black on a break of 33, and O'Sullivan finally showed a glimpse of his earlier form with an excellent response of 63, enough