Dogs skipper Bontempelli tallied just four disposals during the crucial second and third quarters at the MCG on Friday night as the elimination final slipped away.
The 28-year-old star desperately tried to drag his side back into the contest at the start of the final term, but the damage had already been done.
The Bulldogs ultimately fell to a 14.15 (99) to 9.8 (62) loss - their fifth elimination final defeat in the past decade.
"He might've got stuck on (the bench) for a minute or two longer, but no, he was OK," Beveridge said when asked about Bontempelli's fitness.
"He tried to lift us in the last quarter, he kicks a goal and almost kicks a second.
"That was the message at three-quarter time; after all our hard work (through the season) we've got to make a fist of this.
"We started that last quarter like we could but then we just squandered a couple of forward forays where we possibly could've put a bit of pressure on.
'Flat as the proverbial tack': Bulldogs head coach Luke Beveridge (Joel Carrett/AAP PHOTOS)
"In the end there was a significant gap on the scoreboard and they earned it."
Bontempelli finished with 18 disposals and one goal in a midfield unit that was comprehensively outplayed by an exuberant Hawthorn outfit.
The Hawks dominated contest possession (150-125) and generated a huge advantage in forward entries (59-39).
After leading by 12 points at quarter-time, the Bulldogs were outscored nine goals to two during the second and third quarters when the game was on the line.
"Everything that we've been pretty good at - and you look at the KPIs over the year - they went away from us," Beveridge said.
"How much of that it us and how much is Hawthorn? Credit to them, they looked slick across the ground and put us under enormous pressure.
"We didn't cope with it as well as we needed to and they rightfully won the game, pretty convincingly in the end.
"We're as flat as the proverbial tack, as you can imagine."
Beveridge, the Bulldogs' 2016 premiership coach, urged his players to "stick to the process" and remain united in pursuit of future success.
"We've got a strong environment, we're connected spiritually and emotionally, and there's a lot of care," Beveridge said.
"So know's the time to make sure that we get through the disappointment together and have a resolve as we part to make sure we look after ourselves and start next year in the right vein."
