Northampton survived a major scare at Franklin's Gardens before launching their Heineken Cup campaign in bonus point fashion, by beating Glasgow 24-15.
The Saints, tournament runners-up to Leinster in 2010, trailed 15-0 before they turned the Pool Four clash on its head through three tries in six minutes either side of half-time.
Centre George Pisi touched down twice, while fly-half Stephen Myler's try just after the break nudged Northampton ahead for the first time before wing Vasily Artemyev's late effort sealed it.
Myler and Ryan Lamb each booted a conversion to help wipe out an alarming deficit as Saints conceded tries to Glasgow flanker Josh Strauss and wing Sean Lamont after centre Peter Horne kicked an early penalty and converted Strauss' try. Myler, though, missed four shots at goal that could have proved costly.
After hardly seeing the ball for 10 minutes, Northampton almost struck an opening scoring blow when wing Ken Pisi sprinted clear from inside his own 22. Glasgow, though, had enough defensive numbers to thwart the danger.
Ken Pisi was involved with Saints' next scoring opportunity after Glasgow went in front through a Horne penalty, but this time he could not ground the ball under pressure from a superb Lamont tackle. And Glasgow stormed back upfield, launching a succession of drives deep inside Saints' 22 that ended with Strauss touching down. Horne converted, and Northampton had it all to do, 10-0 adrift.
Northampton were visibly frustrated at their failure to finish chances, and matters deteriorated eight minutes later when more impressive work by Glasgow's forwards and some slick passing from their backs ended with ex-Saints player Lamont powering over. Horne could not add the touchline conversion, but Glasgow's 15-point advantage stunned the home crowd during a half the visitors looked to end by pushing for another try.
But Northampton dug deep when they had to, stunning Glasgow with two tries during first-half injury time. George Pisi's opener came after his slashing midfield break sparked a period of concerted attacking pressure, then he finished off superb approach work from his brother Ken as Glasgow's defence found itself scattered to all parts.
Myler converted Pisi's second try, and Saints trooped off just three points adrift when it could have been so much worse. Glasgow were forced into making an interval change when fly-half Ruaridh Jackson, who suffered a knock during the opening 40 minutes, was replaced by Niko Matawalu, with Horne switching to number 10 duties.
They were powerless to halt increasing Northampton momentum, which was emphasised by a 45th-minute charge from prop Soane Tonga'uiha that created a platform for Myler to score. And when Artemyev sprinted over six minutes from the end of normal time, there was no way back for the visitors, although they could yet have a considerable say in the outcome of a group that also includes Castres and Ulster.