By ROGER PANTING

Gloucester .........23pts Tries: Blake 30 Penalties: Carreras 6, 18, 34, 49, 60, 65 Ospreys............... 13pts Tries: Giles 13Conversions: O Williams 13 Penalties: O Williams 22, 40 Main man: Zach Mercer on the front foot for Gloucester PICTURES: Getty Images/ AlamyONCE again the goal-kicking of Santiago Carreras was the key factor in Gloucester progressing in the European Challenge Cup. Last Friday, the Argentinian international fullback kicked 15 points in their 30-25 win over Castres and he followed up with another 18 points as his side won an attritional ga...