Joel Freijah kicked four goals as the Bulldogs took control early and resisted a strong Swans fightback in their 16.9 (105) to 14.12 (96) victory at the SCG on Friday night.
It was the Dogs' third-straight win and improved their record to 9-6, solidifying their spot in the top eight, while the Swans (6-9) now face an uphill battle to play finals.
Bulldogs captain and superstar Bontempelli kicked a clutch third-quarter goal but was relatively quiet with just 18 disposals in his 250th AFL game.
His protege Freijah booted a career-best four majors from 23 touches, while Lachie Bramble (28 disposals), Ryley Sanders (25) and Bailey Williams (18) played important roles.
"It wasn't the usual suspects tonight who necessarily drove the bus home in the end," Bulldogs coach Luke Beveridge said.
"It was some of the lads who maybe haven't been the matchwinners.
"It's great to be able to celebrate for a man (Bontempelli) who's just been such a trailblazer and a significant figure at our football club on and off the field.
"We paid tribute to him tonight, so I'm really glad for him that we could win and that he has a pretty sweet taste in his mouth."
Bulldogs key forwards Sam Darcy and Aaron Naughton both kicked three early goals to fire their team to a 28-point lead midway through the second term.
But the Swans hit back as Isaac Heeney (five goals) threatened to drag his side over the line in a fiery contest, with the fuse lit when Tom Papley targeted Darcy before the opening bounce.
Sydney ruckman Brodie Grundy was also outstanding after quarter-time and the lead change hands six times during a rollicking third term, when the two sides kicked 6.1 apiece.
It became an arm-wrestle in the final quarter and the Bulldogs hung on, with Hayden McLean blowing a late chance to set up a grandstand finish.
McLean's miss with about one minute left continued the trend of the night as the wayward Swans kicked 4.10 from set shots to the Dogs' 8.5.
"The last two weeks it's been an issue. It's something that we need to train," Sydney coach Dean Cox said.
"We need to make sure that we're also having shots from decent spots on the ground to give ourselves the best chance to maximise that.
"But having said that, when we do get our chance, we need to take control and execute."
Sydney lost Tom McCartin to illness before the bounce and fellow defender Dane Rampe to a calf injury after halftime, while Aaron Francis faces scrutiny over a swinging arm to Lachie Bramble's body in the third quarter.
Francis and direct opponent Rory Lobb can also expect fines from the match review officer over their prolonged wrestle in the final term.
