Saints progress to the last four, while the Wolves will have to wait to find out who they must beat if they are to join them in the last four.
"We did not attack as well as we needed to. We were impatient and did not ask enough questions of Saints when we had them in their area," Smith said. "We let them off the hook. It did not flow for us."
He added: "We were good defensively for much of the game. But they took advantage when we slipped up. We were not at our best and need to be at this stage of the competition.
"You have your good days and some not so good. It was not disastrous but you need to be at your best. The players are responsive, we will work hard this week and now we get to play another game."
Saints boss Mike Rush was delighted with the win that takes his side 80 minutes away from a seventh consecutive Grand Final appearance.
He said: "Defensively we were outstanding playing against a quality side with some smart players. We withstood 20 tackles on our goal line and that was a true reflection of the determination this squad has got.
"Others have doubted our forwards this year but it was nice to prove people wrong. When questions are asked the players take it and come back a little bit stronger and hopefully that little bit better."
He saved particular praise for the effort of man of the match Sia Soliola.
He said: "Sia was enthusiastic and charged around at 3,000 miles an hour at first. But every time he goes on to the field he plays for the club and the town and I don't think you can ask any more of a player."