The AFL premiership race tightened on Saturday, when Hawthorn were made to look "silly" in a 29-point loss to Melbourne at the MCG.
The Hawks were denied a 10th straight victory by the determined Demons, reducing their buffer atop the ladder to just one game.
It wasn't the only headache for Hawthorn coach Alastair Clarkson, with defenders James Frawley (shoulder) and Ben Stratton (pectoral) added to the club's injury list.
The match review panel is likely to scrutinise two incidents involving Cyril Rioli, who returned with a bang - and a bump - as he threatened to drag his side over the line.
Rioli's fourth goal put the Hawks in front late but Melbourne booted the final five goals of the game to prevail 17.8 (110) to 11.15 (81).
If the flag favourites slip up against North Melbourne and/or West Coast in the next fortnight, it could cost them a spot in the top four.
Such a scenario would be an immense blow to their hopes of a fourth straight premiership.
Clarkson wasn't willing to look any further ahead than a round-21 clash with North.
"We're going to need to play a little bit better than today if we're going to challenge them," Clarkson said.
"We were just well below our best ... they made us look silly at times.
"But we've won nine out of 10 (in a row). There's 17 other clubs in the competition that wish they had that record."
Rioli caught Clayton Oliver high with a first-quarter bump, while he dumped Neville Jetta in a bruising tackle during the second term.
"Cyril might still get a week but, if Oliver stayed down or came off the ground, it might be a much harsher penalty," AFL legend Wayne Carey said on Triple M radio.
"Oliver's got a hard head. He bounced up and played on - that helps Cyril a lot.
"The lifting tackle will be looked at."
Clarkson was cautious but confident regarding Rioli's bump.
"I can't say anything about it," he said.
"I didn't think there was anything in it but the powers that be will decide that.
"We would have been in a lot more trouble if we didn't have Cyril. He was pretty exciting."
Frawley was a late withdrawal, while Stratton played no part in the second half.
"We need to get both of those guys assessed during the week to see their availability," Clarkson said.
"It meant we were a bit less stable in our back end than we'd like ... that's not usually the way we defend."
Clarkson also lamented his side's sloppy goal-kicking, with Jack Gunston's haul of 2.4 making him the worst offender.
"You've got to take your chances," Clarkson said.
Midfielders Dom Tyson, Nathan Jones and Jack Viney were all magnificent for Melbourne, while ruckman Max Gawn produced arguably the highlight of his incredible season.
Gawn clutched eight contested marks, tallied 41 hit-outs and booted a goal in a best-on-ground performance.
"To win those games, you have to have everyone playing good footy and we did," Demons coach Paul Roos said.