Maguire lost 6-4 to Stuart Bingham but it was the sixth frame that probably cost him the match. Trailing 3-2, having fought his way back from a two-frame deficit, Maguire looked set to level things up in with his hand on the table in the middle of a 60 break as he lined up a red.
What followed surprised the whole crowd and probably Bingham as Maguire called a foul on himself with a push-shot, leaving Bingham to clear up and steal the frame for a 4-2 lead.
"I have played worse and won before but I gave away two frames, particularly the one where I pushed the red," Maguire said. "That was just pure stupidity and Stuart made a good clearance. In the final two frames, I didn't even see a red. Stuart played really well and all credit to him."
It was also bad news for fellow Scot Graeme Dott as he went out on the neighbouring table to Shaun Murphy.
The former world champion was never really at the races as Murphy raced into a 3-1 lead at the interval and it did not take long for world No.4 to wrap up a 6-2 win.
In the afternoon session, there were wins for Matthew Stevens, who saw off Marco Fu by 6-4, and Ali Carter, who took down Judd Trump's conqueror Mark Joyce by 6-2.