The world number eight and 2005 world champion needed all of the seven frames to beat his opponent.
He looked set for a comfortable victory when wins of 74-1, 86-26 and 65-44 left him just one frame from the win.
British Open
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20/08/2021 AT 19:13
However Evans hit back with three consecutive frames of her own to push Murphy to a final-frame decider.
Murphy saved a match-high break of 130 to pull off a 134-0 win.
Evans is the first woman to compete in the Champion of Champions tournament.
British Open
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20/08/2021 AT 16:35
British Open
Walden ends Higgins' bid for record fifth British Open title, full last-16 draw
20/08/2021 AT 14:02