The 2004 UK champion Maguire made a record six centuries in a best-of-17 frame match in Saturday's 9-5 win over world number two Neil Robertson – an astonishing feat matched by Shaun Murphy in his 9-8 defeat to Mark Allen on Tuesday night.
But unlike his opening match behind closed doors at the Marshall Arena in Milton Keynes, world number 14 Maguire never had to be at his best to overcome Trump, who surprisingly toiled for any level of consistency as his feared long game largely went AWOL.
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"In good conditions, I play well, it's just a shame the conditions were so bad," said world number one Trump, who has lifted a record six ranking events this season.
I think I struggled the whole tournament really with the conditions. The conditions were pretty poor and that is why the standard was so bad.
"I think if the conditions are good, I seem to play well but when it's (like that) out there you are fighting a losing battle really.
"It's too hot to play snooker today I think."
Maguire – who is only in the event involving the top eight on the world one-year list as first reserve after Ding Junhui opted not to fly from China - trailed 4-2 as Trump produced breaks of 97 and 57, but his scoring prowess was missing with Maguire enjoying 51 and a wonderful 132 to ensure the first session ended level at 4-4.
Apart from a knock of 79 to lead 6-5, Trump could not escape from his state of torpor and was duly punished with Maguire popping up to win the next four frames including a fine run of 55 in establishing a merited 8-6 advantage with a closing 56 providing the platform for his victory.
The Scotsman will face three-times world champion Mark Selby or former Masters holder Allen in the final over the best of 19 frames on Friday.
Maguire is bidding to win his first ranking event since the 2013 Welsh Open and could land £250,000 if he claims the title on Friday – a £150,000 first prize and a £100,000 bonus for topping the money list over the three events sponsored by Coral, the World Grand Prix, the Players Championship and the Tour Championship.
"I'm over the moon," said Maguire. "I think tonight I nicked the close frames. They are the same as making centuries. I'm just delighted."
Trump must regroup as he bids to become the first maiden winner of the World Championship to successfully defend the trophy next month. He will be in action on the opening day of the event at the Crucible Theatre on 31 July.

Tour Championship draw

Quarter-finals (best of 17 frames)
(All sessions start at 1:30pm and 7pm BST)
  • Neil Robertson 5-9 Stephen Maguire (Saturday)
  • Judd Trump 9-4 John Higgins (Sunday)
  • Mark Selby 9-6 Yan Bingtao (Monday)
  • Shaun Murphy 8-9 Mark Allen (Tuesday)
Semi-finals (best of 17 frames)
  • Stephen Maguire 9-6 Judd Trump (Wednesday)
  • Mark Selby v Mark Allen (Thursday)
Final (best of 19 frames)
  • Stephen Maguire v Selby/Allen
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