And Smith has dubbed his side's must-win clash with Biarritz as the toughest test of his career
And the Saints have been handed a double boost ahead of their crucial Heineken Cup match with French champions Biarritz on Saturday.
The Saints need a win to stay on course for this season's quarter-finals, with their final pool fixture away to Ulster next Friday.
Northampton and Biarritz both currently have six points at the head of the pool, with Ulster also still in contention on four points.
But the Saints enter the match on the back of two successive league defeats, including last Saturday's 22-10 loss at home to London Irish.
Smith said: 'We know that if we win on Saturday then we will go top of our pool and be in pole position with regard to the quarter-finals.
'But we know how dangerous Biarritz are from our first meeting with them this season, and it is going to be a huge challenge for us.
'I don't think I have faced a bigger challenge in my coaching career.'
Northampton Saints: N Beal; O Ripol, C Hyndman, J Leslie (capt), B Cohen; P Grayson, M Dawson;T Smith, S Thompson, M Stewart, S Williams, R Hunter, G Seely, M Soden, M Connors.
Replacements: D Richmond, C Budgen, R Morris, J Phillips, I Vass, J Brooks, P Jorgensen.