Saracens win means that they, Munster and French side Racing Metro 92 are all still fighting for a lucrative quarter-final place with two rounds in the Pool stages to play in the New Year.

Saracens Owen Farrell and Ronan O'Gara of Munster enjoyed a rare old kicking duel with the Englishman putting his nightmare performance in the first leg to bed to clinch a vital win.

Farrell and O'Gara swapped early penalties before Saracens crossed for the game's first try after a clever kick by scrum-half Richard Wigglesworth led to wing David Strettle crossing in the corner.

Farrell added the conversion to give the home side a 10-3 lead midway through the second half before the England fly-half through an interception pass which saw wing Doug Howlett finish with a try for Munster.

The former All Blacks wing ran in for his 10th try in the Heineken Cup and fly-half O'Gara added the extras to claw Munster back level at 10-10 at half-time at Vicarage Road.

The veteran Irish international O'Gara and England rookie Farrell then swapped penalties at the start of the second-half before Saracens found themselves down to 14-men.

Flanker Will Fraser was shown a yellow card by French referee Jerome Garces for a high tackle on Munster's Howlett, but the visitors failed to score a single point during the 10 minutes with an extra man.

O'Gara missed a penalty but Saracens stretchered their lead with a fourth Farrell penalty to secure a vital victory for the English side to keep their qualification hopes alive.