Complex sentence: Maguire caused an upset when he Higgins 5--3, losing the first two frames before winning the next four, after which he said he had "starting to think about winning it now".
Split into simpler sentences: Maguire caused an upset when he beat Higgins 5--3, a match that saw Maguire lose the first two frames before winning the next four. After the match Maguire he said he had "starting to think about winning it now".