Northampton kept alive their chances of reaching the knock-out stages of the Heineken Cup by grinding out a forgettable victory over Italian strugglers Overmach Parma.

The Saints clinched the bonus point they needed four minutes into the second half when wing Chris Wyles streaked over in the corner to add to first-half scores from Robbie Kydd, Paul Diggin and two conversions by Carlos Spencer.

But although they added two further tries when Soane Tonga'uiha and Sean Lamont struck in the final 10 minutes, it was hardly the avalanche of points expected after last weekend's 68-21 victory in Italy.

However, given the scale of the injury crisis at Franklin's Gardens - with scrum-half Ian Vass forced into an unfamiliar fly-half role because of injuries to half-a-dozen midfield backs - most of their failings were forgivable.

Biarritz, in action against Borders on Sunday, will surely top Pool Six but the Saints have a decent chance of qualifying as one of the two best runners-up and have now banked 15 points and 22 tries from their first four games.

The extensive changes to their side did not look much of a handicap when Spencer threaded a chip through Parma's backline for Kydd to open the scoring in the eighth minute with the New Zealander converting for good measure.

Northampton were guilty, though, of being too ambitious from long-range for most of the game and Fijians Mano Vosawai and Nadridi Sego offered a powerful ball-carrying presence to keep the visitors in the game.

Parma were really struggling at the set-pieces, though, and they buckled after referee David Changleng finally lost patience with their front row and sent prop German Fontana to the sin-bin.

The next scrum was also pulled down and Northampton were awarded a 33rd minute penalty try which Spencer converted. He then led the break-out which saw Diggin take advantage of some soft tackling to add a third try three minutes before the interval.

That defensive weakness in open play was soon exposed again when Wyles was allowed to surge over in the left-hand corner four minutes into the second-half to secure the bonus point Northampton needed.

To their credit Parma then dug in once more and it took another 15 minutes for Northampton to score again when Tonga'uiha was bundled over to claim his first try for the club and Spencer stroked over the conversion from the touchline.

The Italians even staged a late rally when lock Luke Tait intercepted and got within five metres of the line before running out of steam and being dragged down by the cover defence.

That was the cue for Northampton to go straight down the other end and score their best try of the game, some neat passing opening up the space for skipper Matt Lord to send Scotland wing Lamont sliding over on the right.