Thistle equalised in the 21st minute when holding midfielder Cullen Spawforth hit an inswinging corner from the left wing, and centreback Ryan Anderson scored with a glancing header to the far post.
In the 35th minute, a midfield passing movement culminated in White getting in behind the Marist defence and sending in a pinpoint cross for Davies to meet coming in from the left to nod in at the far post. It was 2-1 at halftime.
Somerton made it 3-1 when he hit a free-kick from almost 25 metres over the defensive wall and into the net off the underside of the crossbar.
Thistle's fourth goal came in the third minute of added time. Spawforth, on the right flank 35 metres out, put in a cross towards the far post. The ball was caught by the wind and drifted over the keeper's head and into the net.
Blair said that in a good team performance, Davies, Somerton, White and Anderson were outstanding.
Midfielder Jarom Brouwer was unable to travel because of work, so Nick Land played a holding midfield role alongside Spawforth, and Alan Zarate came in as an attacking link.
Zarate, who played for Thistle Reserves on Saturday, played well for the 65 minutes he was on the field yesterday. He was replaced by Ash McMillan, who had also played for the Reserves. He took a defensive midfield role, allowing Land to move forward into Zarate's position.
