Welsh referee Tim Hayes gave Saracens two penalty tries as they edged past Glasgow in their European Challenge Cup opener at Vicarage Road on Sunday.

The Scottish side led 16-10 at half-time, on the back of a try to winger Francisco Leonelli and the boot of Dan Parks, but referee Hayes became the toast of more than 4,000 home fans by awarding his second penalty try of the match.

Glasgow salvaged a losing bonus point with a 73rd-minute touchdown by former rugby league winger Hefin O'Hare, but Saracens held on for the win.

The English club opened the scoring through the boot of Glen Jackson before Leonelli's well-taken try and four goals from Parks gave the visitors a healthy 16-3 advantage.

A penalty try late in the first half was the start of Saracens' fightback, and a try to Kevin Yates and the second penalty try gave the home side 23 straight points and the victory.