Chris Boyd admits Harlequins are going to be a 'handful' for Saints at Franklin's Gardens tonight (kick-off 7.45pm).
But Boyd's men are desperate to bounce back after feeling 'somewhere between disappointed and angry' about their display at Gloucester last weekend.
Saints suffered a 27-16 opening-day defeat at Kingsholm, failing to turn possession into points, particularly during the second period.
They got on the wrong side of the referee and also produced a string of unforced errors.
And Boyd knows his side will have to be much better if they are to see off Harlequins, who hammered Sale Sharks 51-23 at The Stoop last Saturday.
"It was a great win for them," Boyd said.
"They didn't have a great pre-season - they got a couple of wins but lost to Glasgow.
"But I thought they were really good against Sale, took their opportunities really well.
"They've got a lot of individuals who are a handful and played with a lot of confidence so they're going to be a tough opponent here tonight."
On the mood in the Saints camp, Boyd said: "We were somewhere between disappointed and angry about our performance at Gloucester.
"You don't win games of football with giving away that many penalties and unforced errors.
"The errors and penalties were disappointing but the adherence to what we're trying to do gave us some positive signs.
"While it wasn't the result we wanted and we were disappointed, there were certainly some positives."