Weir added his second just before Eric Escande crossed for the first try for Montpellier. Bustos Moyano's conversion gave the visitors a 10-6 advantage.

But it was Weir with two penalties before the break that pushed Glasgow back into the lead at the interval.

Replacement Ruaridh Jackson stretched that advantage after the break and wing Federico Aramburu's touch down five minutes from time to clinch the victory for the Scottish side.

Masi Matadigo grabbed a late try for Montpellier which gifted the visitors a losing bonus-point.