Lines did not give up however, and thanks to working with coach Steve Prest had a successful 2007–08 season in the PIOS, where he won one event and reached the final of another to finish second in the top 8 qualifying for the main tour. He carried his fine form into the 2008–09 season as he performed consistently to finish in the top 64 and maintain his tour place. Better was to come during the next season, as Lines reached the last 64 of the Shanghai Masters and the last 48 of the Grand Prix, before a remarkable run in the UK Championship. He defeated Xiao Guodong, Ian McCulloch and Nigel Bond to qualify for the venue stages; there he convincingly beat Marco Fu 9–3, then caused an upset by edging out Mark Williams 9–8 to reach his second career quarter-final. Despite the 5–9 loss to Stephen Maguire, this performance could've allowed Lines to return to the top 48 of the world rankings, but another drop in form resulted in three opening round defeats in the remaining tournaments of the season to leave him ranked 50.