Northampton go into the first of a European Challenge Cup double-header against the west country side knowing two wins will go a long way to sealing their passage into the quarter-finals.

Saints sit top of pool two after racking up 50-plus points in wins over Toulon and Montpellier, but tomorrow they will be up against more familiar foes in Bristol, who they meet five times this season.

And they will be spurred on by the memory of a last-ditch Guinness Premiership defeat in their most recent encounter at the Memorial Stadium last month.

Diggin, though, believes fly-halves Spencer and Myler, who looks set to carry on his role at full-back, have the lock-pickers to open up Bristol's defence at fortress Franklin's Gardens tomorrow.

"We have got a fortress up here now," said Diggin. "We haven't lost for 18 months at home and we really want to put a show on for the fans because last weekend's defeat at Gloucester was disappointing.

"Bristol have got a press defence, they come in from the outside, so it is like a blitz defence.

We have been working on ways that we can pick that apart, going on the outside and through the middle.

"And because of the way they defend there will be gaps everywhere, we have just got to pick the right ones.

"In Stephen and Los we have the players to do that.

"Bristol's defence is high risk or high reward, they could get you with a tackle behind the gain line, but if you work it properly you can identify the space. Hopefully Los and Myler will pick them out and we can run the right lines."

Saints have registered new lineout lynchpin Juandre Kruger for the European Challenge Cup, with Academy No.8 Rob Milligan dropping out.

But director of rugby Jim Mallinder says the South African 'probably' won't play tomorrow after turning his ankle ahead of the trip to Gloucester.