The Falcons are tipped by many for relegation to the Championship, following the loss of some of their best talent - such as scrum-half Micky Young, prop Kieran Brookes and number eight Alex Gray - during the summer.
Bath also did the double over their hosts last season but McGeechan, now in sole charge following the departure of Steve Meehan, expects a tough examination at Kingston Park.
"We beat them twice at the end of last season, but playing a side at the beginning of a season is always a bit different," he said.
"Last year, their confidence wasn't high and they weren't that relaxed, but all that goes away with the beginning of a new season.
"We expect them to do things with a bit more ambition and confidence, and we have to match that. We know how we want to play and we know the shape we want to put out on the field."
McGeechan will hand debuts to summer signings lock Ryan Caldwell, flanker Carl Fearns and centre Dan Hipkiss, with Academy prop Kane Palma-Newport also getting a chance.
Newcastle boss Alan Tait, on the other hand, has a host of players out injured including Ryan Shortland, Jon Golding, Matt Thompson, Rikki Sheriffe and Redford Pennycook.
But the former Scotland centre has done his homework on the West Country side and hopes to surprise McGeechan, who he played under in the British and Irish Lions' triumph in South Africa in 1997.
"Our performances in our three warm-up games have been good," he said. "You don't realise how important friendlies are, and we didn't get the opportunity to play many last year.
"We have had Bath watched in their warm-up games and we have analysed them in detail, identifying where their strengths and weaknesses are," he said.
"I know roughly how Sir Ian McGeechan likes to play and how he gets his forwards up for a game.
"The lads have really gelled well off the field but of course it is on the field where it matters most, but I can't complain about our preparations leading up to the game."
Saturday's other action sees new Wasps boss Dai Young facing a stern opening assignment against defending champions Saracens at Twickenham, while London Irish and Harlequins meet in the other game at the annual London Double Header.
Last year's losing finalists Leicester begin their quest to reclaim the title by hosting Exeter at Welford Road while Worcester make their return to the top flight at home to revamped Sale.
The final game of the opening weekend sees last season's losing semi-finalists Northampton and Gloucester clash at Franklin's Gardens on Sunday.
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