It's been all change at Firhill this summer with the departures of big-name players Dan Parks and Kelly Brown, and the retirement of Thom Evans due to injury, but Beattie believes Lineen's young side can belie their underdog status this season.
He said: "On this evidence Glasgow will be a force to be reckoned with this season. I have no doubt about that.
"I think the performance against Leinster showed that all these young guys like Richie Gray, Calum Forrester, Ryan Wilson, Duncan Weir, Richie Vernon and Ruaridh Jackson can take the side forward.
"Glasgow's ability to keep the tempo up wore Leinster down and there's good signs."