Victor Wanyama and Charlie Mulgrew also scored as the SPL champions tuned up for their Champions League qualifier second leg against Helsingborg in midweek, while Ross Draper nicked two late consolation efforts for the Highlands side.

Celtic got themselves into the lead early on, when an Adam Matthews corner was met by Wanyama, who headed home after four minutes.

Midway through the first half the visitors doubled their advantage.

Wanyama found Filip Twardzik on the halfway line, who then found 18-year-old Watt racing forward. He beat Simon King before curling the ball beyond Esson from the edge of the box.

Mulgrew powered a strike past Esson three minutes after the break to put Celtic 3-0 up, and the match was over as a contest just after the hour mark when Watt scored his second.

Draper salvaged some respectability for his team when he netted a double late on, but the three points were already in Celtic's keeping.

In other results, Kilmarnock had goals from Jude Winchester, Rory McKenzie and Borja Peres to thank for their 3-1 win over Dundee United at Rugby Park, while United's city rivals Dundee went down 1-0 at home to Ross County.

And Hibernian continued their strong start to the 2012/13 season, with strikes from Paul Hanlon and Eoin Doyle firing them to a 2-0 home win over St Johnstone.