Melbourne coach Dean Bailey demanded an instant end to an AFL trial rule after his club's perfect pre-season start in Adelaide on Friday night.

The Demons downed Adelaide by 10 points and Port Adelaide by nine points at AAMI Stadium on the opening night of the pre-season competition.

In the final of the three games, Adelaide allowed Port just three scoring shots on their way to a 0.6.4 (40) to 0.1.2 (8) triumph.

The Demons' dual victories came as the AFL trialled a new out of bounds rule - a free kick against the team last touching the ball before it crossed the line.

The law created confusion in all three games, with unclear umpire interpretations about whether the ball was in contest before crossing the line.

If deemed out of bounds from a contest, no free kick was paid.

The rule won't be tested again in further rounds of the pre-season competition, but Bailey called for it to be instantly scrapped ahead of further matches this weekend.

"I'm not sure there is much I like about it ... I don't like the rule," Bailey said.

"I'd drop it straight away - you have had your experiment.

"I don't think it's a rule that is going to benefit either team or the game."

Bailey's Demons overpowered Adelaide with a first half blitz of four unanswered goals on their way to a 0.5.4 (34) to 0.3.6 (24) win in the pre-season opener.

In game two against Port, Melbourne kicked the only two goals in the second half to log a 0.5.6 (36) to 1.2.6 (27) win.

"We came here wanting to play as well as we could, a different format and all the different rules that were involved in it, it was always going to be an experience," Bailey said.

"We are pleased we got through the games with no injuries, just as important as winning the games, so that was pleasing."

Adelaide ended the triple header comprehensive winners over their home town rivals, Port.

The Crows were considered disadvantaged by having a break between games, and rested a core of eight senior players from their opening match.

But the return of the likes of Scott Thompson, Brent Reilly and Brad Symes was influential against the Power, with the trio featuring prominently in a win never in doubt after Port was restricted to just one point in the opening half.

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