NORTH Melbourne coach Dean Laidley was delighted with the performance of his relatively young side that beat Fremantle by 36 points at Subiaco Oval in the NAB Challenge match, but not with the news that Jess Sinclair has suffered a serious thumb injury.

The Kangaroos kicked the last eight goals of the game to end up convincing winners, but Laidley confirmed that Sinclair would need surgery and could miss up to two months.

"He has done some ligaments in his thumb and dislocated it, so will miss about six or more and need surgery," Laidley said.

"After the last two years we have lost Jesse Smith and Nathan Thompson for the season in practice games, so we are getting used to it. It will give someone else an opportunity, though."

The match was certainly scrappy in the first half, but the Kangaroos were the team to lift after the main break. That pleased Laidley no end, as well as the form of ruckman Hamish McIntosh and several youngsters.

"Our attention to detail in the second half was pretty good after being scrappy early on. We started the game with 25, which was one less than Fremantle because we didn’t want to pay particular attention to the result, but then we lost Jess Sinclair. It ended up meaning that most of our guys got good minutes, so it was a good hit out," he said.

"Hamish was really good, as was David Hale. (Daniel) Harris, (Andrew) Swallow, (Leigh) Harding and (Matt) Campbell were pleasing too. Hamish has played nearly 50 games, is going into his sixth season and is coming forwards in leaps and bounds."

North Melbourne now plays Melbourne in its final pre-season match at Casey Fields next week and Laidley will welcome back stars Daniel Wells, Nathan Thompson, Brent Harvey and Adam Simpson.

"We will try to fit them all in next week. Wells, Thompson, Harvey and probably the captain will play, so they are four or five really important players," he said.

"Some of the young guys put their hand up again as well. Scott Thompson was excellent again down back, (Gavin) Urquhart and (Matt) Riggio showed a bit, as did Campbell, (Matt) Thomas and Scott McMahon forward. Even though Robbie Tarrant didn’t get much of the ball, his work rate is enormous and that will hold him in good stead."