World number one Judd Trump slipped to a 4-3 defeat against Elliot Slessor, while Shaun Murphy lost by the same score to Jackson Page in the fifth round of the English Open.
Slessor, ranked 23rd in the world, opened up a 2-0 lead in Thursday’s afternoon session at the Brentwood Centre, helped by a break of 67.
Trump, who is yet to reach a semi-final this season, responded with two half-centuries as he reeled off the next three frames.
However, Slessor compiled a break of 79 to force a decider and booked his quarter-final place against either Mark Allen or Ding Junhui with a run of 64.
Meanwhile, reigning Masters champion Murphy knocked in breaks of 93 and 102 as he fought back from 3-1 down to 3-3 against Page.
While both players had opportunities in the seventh frame, Welshman Page held his nerve to seal victory and will now face Wu Yize or Mark Selby.
China’s Zhou Yuelong also made it into the last eight after breaks of 84 and 71 helped him see off Barry Hawkins 4-2.