Barry Hawkins was the first player to book his place in the semi-finals with a measured 4-2 win against Neil Robertson.
Hawkins, who recently came to within one match of reaching the Masters final, made light work of Robertson after a comfortable win over Judd Trump earlier in the day.
After the match Hawkins admitted it was a relief to kill the game off after taking an early lead.
“I needed to win that final frame,” he said.
“I start collapsing when I’m in front but I’m pleased and I played alright today I think.”
Liang Wenbo exited the World Grand Prix at the quarter-final stage last year but there was to be no repeat as the 2016 English Open winner despatched of Joe Perry.
There was nothing in the match and both players showed great skill in posting some high scores, including a 129 break from Wenbo, before the 29-year-old edged a final-frame decider.