The Warriors' former Wasps wing Thom Evans scored three tries, restricting Bath to a 21-19 lead with almost three-quarters of an entertaining Pool Five encounter gone.

But the Guinness Premiership title contenders dug deep when it really mattered, conjuring quickfire tries for wing Michael Stephenson and substitute centre Shaun Berne midway through the second half.

Stephenson finished with a double, while flanker Andy Beattie also crossed; yet it was fly-half Butch James' goal-kicking that gave Bath breathing space.

The Springboks World Cup-winner slotted six kicks from seven attempts - three penalties and three conversions - to keep the pressure on group leaders Toulouse, who visit Bath next month.

Glasgow find themselves in the familiar position of pondering a pool stage exit - having lost to Bath, Toulouse and Newport Gwent Dragons.

But given the fact they were minus injured half-backs Dan Parks and Mark McMillan, Glasgow gave Bath a surprising amount to think about - and substitute Hefin O'Hare's late try provided a deserved four-try bonus point.

Fly-half Ruaridh Jackson even caused late panic in the Bath ranks by converting his own breakaway touchdown four minutes from time. But the home side prevailed, despite losing out 5-4 on tries and only narrowly thwarting a last-gasp Glasgow break-out.

Glasgow made a storming start, rocking Bath with a sixth-minute try.

The hosts proved slow to react in defence, and slick Glasgow approach work resulted in a try for Evans that scrum-half Colin Gregor converted.

Bath, despite the presence of returning England internationals Matt Stevens and Michael Lipman up front, could not get going as errors abounded.

James opened their account with a 45-metre penalty after 13 minutes. Yet despite the South African's promptings, repeated handling mistakes allowed Glasgow an easier time of things in defence than they might have imagined.

Bath eventually stirred six minutes before half-time when their forwards rumbled Glasgow backwards at a short-range scrum, and Beattie touched down - although referee Alain Rolland required video official confirmation before awarding it.

Any thoughts of Bath taking charge by the interval were set aside when Glasgow stung them with a second Evans try.

Flanker John Barclay, at the heart of a magnificent Glasgow back-row performance, made a telling thrust that proved sufficient to break Bath's defence apart - and Evans finished off in expert fashion.

Gregor slotted the extras - and although James kicked a 38th-minute penalty, Glasgow trooped off deserved 14-11 leaders.

Bath would undoubtedly have received a half-time rocket from head coach Steve Meehan - and they responded by regaining the lead just five minutes into the second period.

Hooker Pieter Dixon spearheaded some relentless work by the Bath forwards, and Stephenson had just enough space to weave his way over in the corner for a try that James improved.

James completed his penalty hat-trick just four minutes later, and Glasgow were suddenly in danger of being run into submission - until Stephenson went from hero to villain and 'gifted' Evans his hat-trick.

The former Newcastle wing could not gather possession under pressure, and his fumble played straight into Evans' hands for a soft try.

Gregor saw his conversion attempt hit the post, but it was another warning to Bath that they risked defeat unless they could consistently raise the tempo.

The unlucky Gregor then had a speculative drop-goal strike rebound off the crossbar - which cued a triple Bath substitution as Lee Mears, Justin Harrison and Jonny Faamatuainu provided reinforcements.

The combined effect was exactly what Meehan wanted as Bath secured a bonus point with two tries inside two minutes from Stephenson and Berne, both converted by James.

The double blast ended Glasgow's brave resistance; yet they still had the final say when O'Hare crossed after a thrilling counter-attack inspired by his fellow wing, Samoan international Lome Fa'atau, before Jackson touched down and converted following his interception of erratic Bath full-back Nick Abendanon's speculative pass.