Neil Lennon enjoyed a "collector's item" when James Forrest's header proved to be enough to give Celtic a 2-1 win over St Mirren in Paisley.

Saints striker Lee Erwin, making his first start since signing from Ross County last week, scored from close range in the third minute only to see it cancelled out by Hoops defender Shane Duffy's powerful header.

While there was no surprise that the Republic of Ireland defender had scored with a header – he scored a similar goal on his debut at Ross County on Saturday – eyebrows were raised when Forrest dipped his head to send a Ryan Christie cross into the net in the 36th minute.

Lennon, whose side moved into second place in the Premiership and three points behind Rangers with a game in hand, said: "The second goal is something we've talked about and worked on where we cross it a little earlier rather than keep working it.

"Ryan has flipped it in on the angle and it's a brilliantly guided header by James.

"He's a player who goes under the radar but he's scored so many important goals for us and he's done it again tonight.

"It's a collector's item. It's a fantastic goal, he's used the pace of the ball to guide it into the top corner.

"It's unsaveable really. We were waiting for the third goal but unfortunately it never came."

Lennon was pleased with Duffy's contribution since signing on loan from Brighton.

He said: "He was disappointed with the goal we conceded but his reaction was great.

"That's two in two for him. If you put the ball in a good area for him he will go and attack it. It's a fantastic ability that he's got.

"We deserved to go in at half-time in front and we scored two very good goals, two headers which is different for us."

St Mirren boss Jim Goodwin said: "Overall, I will take a number of positives from it but I would have liked to have held on to that lead a little bit longer and I'm really disappointed with the two goals that we ended up conceding."