Fraser Brown went over for Glasgow's second try

The wet conditions gave little opportunity for the teams to play their usual expansive style of rugby but Warriors will take their narrow win as a valuable confidence boost ahead of these two teams meeting again in Llanelli in the last four of the EPCR Challenge Cup in two weekends' time.

Scarlets started much the brighter and dominated the opening period. They took the lead with a Dan Jones penalty after 20-plus phases of pressure.

The Welshmen doubled their lead when Sam Johnson was penalised for a high tackle on Kieran Hardy, and Jones once again slotted the kick.

The deteriorating weather was having a huge impact on play with both sides struggling to put together multiple phases.

With ten minutes to go to the break Warriors began to exert some pressure through some smart kicking from Ali Price, Tom Jordan and Stafford McDowall.

Warriors almost opened their account when Ryan Wilson - who could be playing his last game at Scotstoun - was held up over the line.

Then, with just four minutes left in the half, Glasgow worked a line-out to allow Sione Vailanu to break through three tackles to cross the line.

Jordan missed the conversion meaning Scarlets took a single-point lead into the interval.

Scarlets struck first in the second half, with a scrum penalty handing Jones three more points.

Warriors responded well and the they grabbed the lead after 54 minutes when Fraser Brown finished off a line-out maul.

This time Jordan made no mistake from the conversion. Warriors continued to press but they could not find a way to extend their lead.

With the hosts camped in Scarlets' territory, second-row Vaea Fifita stole possession from the base of a Warriors ruck just inside his own 22 and ran the length of the pitch to go over in the corner.

However, referee Chris Busby referred it to the TMO, who ruled that the Tongan had gathered the ball from an offside position. Warriors breathed a massive sigh of relief and were able to hold out for the remainder of the match to secure a hone URC quarter-final spot.

Warriors tight-head prop Zander Fagerson was named man-of-the-match. "We're really happy," said Fagerson afterwards. "It was a big effort from the whole pack. Our pack love to scrum and we knew tonight would be a big battle against a good Scarlets pack. We got the job done, but we know we need to back it up in a couple of weeks when we play them again at the Parc y Scarlets. I think we're getting better every week. We left a few points out there and could have scored more. We could have been more ruthless. We want to get better and it's an exciting time to be part of this squad."