Glasgow overrun Ospreys
Flanker Chris Fusaro also went over and outside-half Duncan Weir added 10 points, while the Ospreys’ only try came from lock Ian Evans.
Three minutes in Van der Merwe caught Dan Biggar’ s up and under, and sprinted 70 metres for the opening try.
Scrum-half Chris Cusiter earned a penalty for Glasgow which Weir kicked to extend the visitors’ lead to 8-0.
Glasgow got a second try on 28 minutes through Fusaro. Weir converted to give Glasgow a 15-0 lead.
The Ospreys tried to get a positive attack going after the interval but were penalised in the Glasgow 22 and Webb was then yellow-carded which allowed Weir put over his second penalty as the Scots extended their lead to 18-0.
Evans eventually crashed over on 51 minutes for Ospreys, a try converted by Biggar. But the Ospreys comeback lasted only three minutes before Van der Merwe crashed over for his second try, converted by Weir.
Five minutes from time Ruaridh Jackson confirmed the Warriors’ win with a penalty.
Ospreys scorers: Tries: Evans. Cons: Biggar. Pens: Biggar. Glasgow scorers: Tries: v der Merwe 2, Fusaro. Cons: Weir 2. Pens: Weir 2, Jackson.
Result: RaboDirect PRO12: Edinburgh 41 Zebre 10. Aviva Premiership: Bath 14 Northampton 18




