Harlequins boss Conor O'Shea felt Northampton's second try in their 18-10 Amlin Cup semi-final win over his side should have been disallowed.
Kahn Fotuali'i raced over from 25 metres after collecting a bouncing ball that squirted out of a ruck to make it 16-3 after 44 minutes, but it looked as if he got a fingertip to the ball as it first flew forward before then catching it at the second attempt.
Television match official Jim Yuille looked at the replays long and hard, but decided he could not see Fotuali'i's fingertip touching the ball and referee George Clancy awarded the try that added to Tom Collins' first-half effort and eight points from Stephen Myler.
Harlequins came back with a converted try from Nick Easter, but Northampton held on to reach their second final of the season after losing the LV= Cup final to Exeter.
O'Shea said: "It looked like he touched it; a feather, but he touched it. All the players thought he touched it and a knock-on is a knock-on.
"But did Northampton earn their win tonight? They did, the game can be very different if the little things happen for you and they didn't happen for us tonight."
When asked if he touched the ball, man of the match Fotuali'i, whose sublime kick set up the first try for Collins, said: "Not at all. I tried to, but I don't really know, if I did it went backwards. I was pretty confident I didn't and it got awarded so...."
O'Shea is confident Mike Brown will be fit for Harlequins' final two games of the season as they look to secure a Premiership semi-final place, after the England full-back came off at half-time.
Brown hurt his knee after being taken out in the air by Jamie Elliott in the third minute, which earned the Saints wing a yellow card.
"Mike is fine," said O'Shea. "The ground was pretty hard there and his knee has ballooned and stiffened up massively. We have a nine-day turnaround; it is just a bad bruise, so he should be okay.
"You don't know what's coming these days, but the yellow card was fine for me."
Northampton director of rugby Jim Mallinder revealed Lions wing George North went off in the first half with a calf injury picked up in the warm-up, but was delighted with Fotuali'i's performance.
"Kahn is a special player," said Mallinder. "There were two outstanding nines on the field. Danny Care has been in great form and we marshalled him well, but I thought Kahn was outstanding.
"Defensively we were very good for 80 minutes and stopped a lot of their threats, Danny Care in particular. We took our opportunities in attack and our half-backs were very good at putting us in the right position."