Hendry, winner of the Regal Scottish Masters, Skoda Grand Prix and UK Championship so far this season, said: "My form drifted in and out during the match, but it's always a great feeling to get through to the final of this event. Alan is very tough to beat."
McManus, the player responsible for ending Hendry's five-year unbeaten run in the Masters with a 9-8 victory in the 1994 final, made the better start.
When Hendry unexpectedly missed a simple yellow off its spot in the opening frame, McManus stepped in with a clearance to pink and led 2-0 thanks to a 78 break in the second.
But the world No 1 produced a typically emphatic response to go into the mid-session interval on level terms at 2-2.
He won the third frame with a 121 break before following up with a run of 86.
McManus was to suffer another body blow in frame five. Leading 58-13, the Glaswegian jawed a black from short range and Hendry produced a 59 clearance to snatch a 3-2 lead.
At that point the favourite looked ready to take control the contest, but McManus knocked in two 61 breaks to regain control at 4-3.
Hendry tied the scores once again at 4-4, then kept his patience to prevail in a low scoring ninth frame, before he applied the finishing touches with a composed contribution of 61.
In yesterday's best-of-19-frames final, Hendry took an early 6-2 lead against England's Ronnie O'Sullivan, who took only 88 minutes to beat Andy Hicks 6-1 in the other semi-final.
O'Sullivan is suffering from damaged ligaments to his foot he sustained on Thursday when kicking an immovable concrete plant pot. "There was no problem today and I cannot thank the people enough who worked on the foot for three or four hours yesterday. They used laser treatment and creams, and I could feel it getting better," the defending champion said on Saturday.Reuse content