But if that didn't confirm it, Jeremy Howe's goal 13 minutes into the final term after a rare regulation mark should have been enough to guarantee a comfortable victory.
The Demons were 44 points clear at that stage.
However, the final 20 minutes were anything but comfortable for the Melbourne faithful as they watched their team concede seven unanswered goals, the last leaving the Bulldogs just two points behind.
Luke Dahlhaus started the run when he ducked a tackle and broke free to kick his only goal on a quiet night.
Tory Dickson was also quiet in his first game since round three, but he marked in front of goal and cut the margin to 33 points.
"It's a funny thing, the human psyche. Sometimes you kick a couple and you think, 'well, let's have a crack at it'," Bulldogs coach Brendan McCartney said after the match.
Have a crack they did, with Will Minson (20 fourth-quarter hit-outs) and Ryan Griffen (two fourth-quarter goals) sparking the run from midfield.
The pair combined superbly at a forward 50 stoppage, Griffen reading his ruckman's tap and snapping a goal that brought the margin to 26 points.
There was a genuine fear among Demons fans that the heist was on at this point, with Brownlow medallist Adam Cooney entering to kick back-to-back goals and cut the margin to 14 points.
Minson and Ayce Cordy both took strong contested marks and converted set shots, challenging the young Demons to hold on to their two-point lead with almost two minutes to play.
Enter Watts, whose three first-half goals were instrumental in setting up the Demons' lead.
The No.1 draft pick from 2008 stood tall one more time, taking a intercepting mark as the Bulldogs went forward to effectively seal the game.
"I remember thinking that 'surely there's about 10 seconds left', and the runner came out and said there was seven minutes," Watts said of the run home.
"I knew it was going to be a fight to the end. It was good by them to come back at us in that last quarter, and great by us to hold on."
Nathan Schmook is a reporter for AFL Media. Follow him on Twitter: @AFL_Nathan
