HAWTHORN coach Alastair Clarkson admits he was left confused by the score review system on Friday night, but says the AFL is on the right path in its search for better goal-line technology.

Collingwood forward Jarryd Blair was awarded a controversial goal in the second quarter of Friday night's clash at the MCG after a lengthy referral.

The ball appeared to have been touched by opponent Taylor Duryea, and was briefly signaled as such by the goal umpire before the decision was sent for review.

The field umpire, however, indicated the goal umpire's decision had been a goal and when the review proved inconclusive, the goal umpire's decision was taken and a goal awarded.

Essendon's Brendon Goddard wrote on Twitter: "The goal review is a debacle … the umpire went to signal touched and changed his mind."

Clarkson said he couldn't work out how the umpires made the call.

"It's a tough one. We're trying to get the game to be better and more accurate, but even sometimes the video review doesn't make it as clear as what you'd like," he said.

"That's a challenge the League will continue to go through, but by and large they're trying their best to get the best system, and all players and coaches appreciate that.

"We're not getting it right all the time, and maybe that was one tonight that might not have been quite right.

"The good part about it is the League is being proactive in trying to get what's best for the game. As long as we continue to try to do that, our game will continue to move forward."

Collingwood coach Nathan Buckley said if the goal umpire's original decision had been for a goal, then the system worked as intended on Friday night.   

"If it came off the hands and it wasn't adjudicated that way and we got a goal when it was a point, well then that's wrong," he said.

"But if the goal umpire thought it was a goal and the vision was inconclusive, well isn’t that what it's designed for?"

The AFL will trial camera technology used in NASCAR racing during Saturday's Richmond-Carlton clash at the MCG as part of its search for a better score review system.

Hawkeye technology will continue to be tested across more games during rounds 22 and 23.   

Twitter: @AFL_Nathan