SWANS coach Paul Roos squared off at his forwards last night after they misfired badly in the team's 29-point loss to their nemesis, Collingwood.

After six straight wins and a week off, the Swans's sweet form turned sour in front of 59,202 fans in a match that was billed as a blockbuster but failed to reach great heights.

Making matters worse, Barry Hall - playing his first game at ANZ Stadium since his infamous hit on Brent Staker - might face scrutiny after appearing to take a swing at Shane Wakelin shortly before half-time. Wakelin hit the deck after Hall's right arm flew past, but got up straight away, suggesting no connection had been made.

It was exemplary of a tough night at the office for the Swans, who were missing the inspiration and skill of the suspended Adam Goodes and fell victim to some classy interjections from Travis Cloke, Paul Medhurst and Dale Thomas.

After a poor first half and third quarter, the Swans staged a revival in the final term, kicking four goals and 31 points. But the challenge didn't last long, condemning the Swans to their first loss since early May.

After a mistake-filled first quarter, the Swans trailed by two points, 1.3 (9) to 1.5 (11). They lost ground in the second, as Collingwood, led by Cloke and Thomas, scored four unanswered goals.

The Magpies went to the main break with a lead of 5.7 (37) to 1.5 (11) and extended the margin in the third term to take a 8.12 (60) to 2.7 (19) advantage into the final term.

The Swans woke up at 9.10pm precisely, smacking three goals - one each to Hall (his only goal), Michael O'Loughlin and Henry Playfair - in the space of six minutes. Collingwood scored once, but misses in the late stages to O'Loughlin, Ryan O'Keefe, Hall and Kieren Jack ended the comeback. Goals to Alan Didak and John Anthony in the dying minutes sealed the game for Collingwood, as O'Keefe squeezed in one more for the Swans.

"Probably our forward line really really struggled, and that was probably the difference in the game," Roos said. "They got some really good goals from Cloke and Thomas and we just couldn't seem to get anything out of our forwards. Sometimes you're best training sessions [lead to] your worst games. We thought we'd planned well, but it didn't work tonight. At the moment, clearly, [Collingwood] feel pretty comfortable playing against us."

Asked about the confusingly poor first half, Roos said: "We kept them to five and we kicked one goal. So in terms of defence we were pretty good. We just couldn't move the ball forward. We just weren't able to get the goals that they got.

"Thomas took a couple of screamers in the goal square and a couple more things like that happened.

"I don't think it was that bad a game. It's just that they took their opportunities, as they tend to do against us, and we just couldn't take any of ours.

"We came back in the end. But even when we were playing well we couldn't take our chances."

Roos said Goodes would have made a positive effect on his side but his absence was not the whole difference.

He could find one good performer off the top of his head - Craig Bolton, who was moved from forward to forward as he was by far the most effective defender for the Swans.

"He had an outstanding game," Roos said. "Kirky [Brett Kirk] dug in and a few of our midfielders, including Jude [Bolton], were good."

Roos said he did not see the incident involving Hall and Wakelin. But, of Hall, he said: "He's been in good form but he had an off night tonight. He's had three games back, two good ones and one where he struggled.

"We lost, we're 9 wins and we've got Hawthorn next week, so you can't really dwell too much on it.

"We're in pretty good shape and we live to fight another day."