Glasgow Warriors claimed a first win at Ospreys in five years after the hosts had no answer to their driving maul.

Johnny Matthews, twice, and Sione Vallanu both scored from line-out drives only for Ospreys to regain the lead through Reuben Morgan-Williams and the boot of Jack Walsh.

However Allan Dell's last-gasp try denied the hosts a losing bonus.

That was a cruel twist for Ospreys who thought they had snatched a third win in a row when Walsh kicked them 23-21 ahead in the 74th minute.

But a game that had swung one way and then the other had more twists to come in a dramatic final three minutes.

Duncan Weir kicked five more points, Justin Tipuric was shown a yellow card and Dell cross for a bonus-point fourth try as Glasgow racked a third win from four games.

The result means Glasgow, without a win in Swansea since November 2018, stay in touch with the leading pack while Ospreys missed the chance to leap into the top five.

Franco Smith made six changes, including Jamie Dobie in the number nine jersey just days after Scotland scrum-half Ali Price's surprise move to Edinburgh.

The switch came at the behest of Gregor Townsend in a bid to get Price more game time and Warriors accepted in the "national interest".

Price's move came in the same week Ospreys announced an arrangement with South African side Cheetahs that saw three players arrive in south Wales this week, though too late to feature in this match.

Wales head coach Warren Gatland was in the crowd to watch as Wales trio Adam Beard, Dewi Lake and Nicky Smith returned to play a key role in the game's opening try.

Ospreys won a scrum penalty then had Glasgow back-pedalling with a line-out drive that ended with Williams crashing through on five minutes.

The centre would have been keen to impress Gatland having missed out on the World Cup and weighed in with a huge tackle on giant lock Greg Peterson, only to leave early following a clash of heads with Weir.

Glasgow's fly-half, making his first start of the season, was shown a yellow card for the high tackle that also prompted George North's return off the bench for Ospreys.

Ospreys almost doubled their lead, but wing Mat Protheroe was seconds too late touching down Morgan-Williams' kick before the forwards spilt a promising line-out drive.

Trailing 10-0, Glasgow finally got their own line-out into gear to stun their hosts with three carbon copy tries to score 21 unanswered points.

Hooker Matthews added to his brace last week against Stormers with another double either side of half-time before Vallanu crossed as home resistance dissolved.

Weir converted all three for a 21-10 lead before Ospreys hit back with 10 quickfire points.

Tipuric's breakdown work earned a penalty that Walsh converted before an over-thrown Glasgow line-out ended with with Ospreys' Morgan-Williams scoring under the posts.

Luke Morgan's kick bounced kindly for the scrum-half and Walsh's conversion made it a one-point game before nudging Ospreys ahead with six minutes remaining.

But Ospreys lost composure at the crucial moment and Glasgow rallied for the late win.

Ospreys head coach Toby Booth said:

"Sport can be cruel and sometimes you don't get what you deserve. It's a tough pill to swallow.

"Glasgow are a very good side, but they didn't do anything we didn't expect. For 75 minutes we more than matched that so we're not going to thrash ourselves over this loss.

"We just didn't nail those key moments when we had the chance early on."

Glasgow head coach Franco Smith said:

"We obviously planned for a bonus point, but not in that manner.

"Ospreys were excellent early on and we had to fight on to stay in the game

"Our maul was doing well so we knew if we could get up field we could have that chance to win late on. We want to play expansively as well, but the line-out is part of our DNA."

"It's a good start to the season and we're going to build on that."

Ospreys: Max Nagy; Luke Morgan, Keiran Williams, Owen Watkin, Mat Protheroe; Jack Walsh, Reuben Morgan-Williams; Nicky Smith, Dewi Lake, Ben Warren, Rhys Davies, Adam Beard, Harri Deaves, Justin Tipuric (capt), Morgan Morris.

Replacements: Ethan Lewis, Garyn Phillips. Tom Botha, James Fender, James Ratti, Luke Davies, George North, Dan Edwards.

Glasgow: Ollie Smith; Sebastian Cancelliere, Sione Tuipulotu, Stafford McDowall (capt), Kyle Rowe; Duncan Weir, Jamie Dobie; Jamie Bhatti, Johnny Matthews, Lucio Sordoni, Sintu Manjezi, Richie Gray, Matt Fagerson, Sione Vailanu, Henco Venter.

Replacements: Angus Fraser, Allan Dell, Enrique Pieretto, Greg Peterson, Alex Samuel, Ally Miller, Sean Kennedy, Tom Jordan.

Replacements: TBC

Referee: Andrea Piardi (FIR)

Assistant referees: Gwyn Morris & John Darcy (WRU)

TMO: Stefano Penne (FIR)