Substitute Callum is the PNE hero

Grayson brought on Callum Robinson for the second half and the substitute found the net within seven minutes in the 2-1 win.

Joe Garner had headed North End into the lead in the first half with his 100th career goal, one which was cancelled out within two minutes by Johann Breg Gudmundsson.

The visitors were reduced to 10 men in the 74th minute, defender Harry Lenoon shown a straight red card for kicking out at Garner after the pair had tangled in the PNE box.

Grayson admitted it had not been the best performance by any stretch of the imagination but he praised his players’ battling spirit as they recorded a fourth win on the bounce.

He said: “We tried to warn the players and supporters what it was going to be like.

“We had the big game and atmosphere at the weekend against Sheffield Wednesday which took a lot out of the players, so this was going to be completely different.

“We had to be patient in what we tried to do and if it wasn’t going right, we had to make sure we put it right.

“There was not a lot if the first half, Charlton changed their shape to combat how we play and we pretty much cancelled one another out.

“We could have played better, we didn’t pass the ball quick enough or as well as we can do.

“It was good to get the goal but then to concede straight away was disappointing.

“At half-time we had to make a decision to try and change things around and that is what I did.

“It was great to see Callum come off the bench and make the impact he did.”

Robinson joined North End for a third loan spell from Aston Villa in January, this the first goal of his latest stay.

Grayson felt it was the right call from referee James Adcock to send-off Lennon.

He also pointed out that Addicks substitute Yaya Sanogo was lucky not to follow Lennon for an early bath for a high challenge on Paul Huntington, Sanogo escaping with a yellow card.

“We finished against 10 men and it could have been nine to be fair, Joe Garner got sent-off earlier in the season for something far less than that,” said Grayson.

“For the red card, the lad has kicked out at Joe in the box, the referee has seen it straight away and sent him off.”