Bingham was not at the races in the first half of the session. He missed with seven escape attempts early in the first frame, looking to clip the yellow, and the Scot went on to make a 71 break to clinch it.
Maguire also took a second frame that turned into something of a scrap after his opening 62 break while the third frame, won by Bingham, was extremely long-winded.
With an awkward spread of reds, and the blue and black out of commission, Maguire was unable to fashion a frame-winning break after Bingham missed a simple colour. The players shared a joke after the Basildon potter left Maguire tight behind the blue on the top cushion - he played it brilliantly off the jaws of the top right pocket to clip a ball halfway down and was unlucky not to cover all the reds.
Bingham went on to make a half-century, potting frame ball black for a 51 before missing a red down the cushion. Maguire conceded soon afterwards.
The Glaswegian went into the mid-session interval 3-1 up with a clever 114 break, which would have been a 121 clearance had he not gone for a cheeky crowd-pleasing double on the black.
Upon their return Bingham missed an early chance but was able to bolster his confidence with a break of 71 to move within a frame of Maguire once more. The Basildon cueman - playing in his third ranking final, having won the Australian Goldfields Open in 2011 and lost to Ricky Walden at the Wuxi Classic at the start of the current season - is enjoying the best season of his career and chasing his fourth title having won the Premier League and two APTC events.
Maguire, meanwhile, is desperate to end a drought of five years without a ranking title having lost to Ronnie O'Sullivan in the German Masters final and by the odd frame to Peter Ebdon at the China Open in 2012.
He boosted those hopes with the sixth frame, making a fine 110; a 145 was on before he lost position on the final red then missed it to the middle left pocket.
But Bingham did not relinquish his improved form so easily, following a 55 run with a 78 clearance to close again at 4-3.
Suddenly Maguire was the man unable to execute, giving Bingham three chances to win the eighth frame. The Essex potter finally finished off his opponent, who looked forlorn in his chair, as the session inevitable ended four frames apiece ahead of the evening session.
That will begin at 7pm UK time and be played to a finish - best of 17 frames.