Kade Simpson says he "nearly marked" the ball that brushed his fingertips and landed into Sam Colquhoun's arms in the dying moments of Carlton's gripping four-point win over Port Adelaide.

Power flanker Colquhoun marked the ball inside 50 from a Brad Ebert kick, with his side trailing by four points with just over one minute remaining on the clock.

The officiating umpire, Brent Wallace, initially signalled the mark to Colquhoun, but the non-officiating umpire had a better view of Simpson's outstretched hands touching the ball.

The Carlton defender pleaded his case to Wallace as Colquhoun looked set to line up the set shot at goal from about 30m out, before the secondary umpire overturned the ruling and a ball-up was called.

Simpson said the umpires made the right call in overruling the original mark.

"I had a big piece of it [the ball]," Simpson told radio station 3AW on Sunday.

"I was talking to a few of the boys after (and) I was like, 'I don't think I've ever seen one of those decisions overturned', but one of the field umpires from the centre of the ground said he called touched straight away.

"It's good how they adjudicate with the earpieces and the right decision was made."

When asked if he had "absolutely no doubt" that his fingers had indeed touched the ball, Simpson said: "More than a finger, I nearly marked it."

Simpson was pleased with how the incident was adjudicated, with the umpires restarting the play via a ball-up instead of allowing play to continue.

"Because play had stopped, the right decision was to ball it up," he said.

"Because the field umpire that did see it was touched was so far away, not too many of the guys heard the decision of touched, and the field umpire that was in control didn’t see the touch and he was paying the mark."

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