Dennis was consistently among the best on the course at each checkpoint, but with so many riders fighting for the top positions it was a tense wait at the end as first Stefan Kung (Switzerland) and Filippo Ganna (Italy) went within a second of snatching bronze away from the Australian.
"I got on the podium and it's a huge relief," said Dennis. "It's been a serious journey to get here and I’m very proud of this medal."
The South Australian went into the Rio 2016 Olympics as one of the favourites but snapped a handlebar extension when in contention for a medal, ultimately finishing fifth.
"It's been a long five years, it's been a lot of ups and downs," said Dennis. "Obviously the last 12 months have been quite difficult for everybody, being reset and refocused 12 months later.
"It's probably been a positive for me in the end because I could really get used to the new equipment and the new environment with the team and really focus purely on this after a bit of a mismatch in the last year with racing and stop-start with everything. Everyone's in the same boat though."
Dennis paid tribute to the support network that has brought him to this point, as he claimed the first medal for Australia at the Tokyo Olympics in cycling.
"It hasn't been easy for any - I'm not going to make excuses for non-Europeans - we can't get back to Australia too easily, and it's been a long time since I've seen all my family, not just my wife and kids," said Dennis. "It's great to have them on the same time zone as me and not have to watch the race at 1am or 2am."
He also had a message for Australian fans and supporters back home, while Dennis is less active posting on social media since an incident during Spanish lockdown saw him take a step back from online presence, it's clear that he still views and appreciates messages of support.
"Thank you for the support," said Dennis. "It's been amazing. There's a lot of stuff on social media that I've seen, and as much as I've been told not to look at it, I do. But there’s a lot of positive support and thank you very much for that."
Rigoberto Uran (Colombia) was the fastest of the early starters in the first two waves of riders, but the favourites for the win were in the final wave of riders and soon posted new best marks at the intermediate time checks out on course with Tom Dumoulin (Netherlands) leading the way.
Dumoulin had taken a break from professional cycling for mental health reasons, but he looked like he had barely missed a second of racing, blazing a trail round the course.
Dennis, Dumoulin, Wout van Aert (Belgium) and reigning world champion Filippo Ganna (Italy) were all around the mark of the fastest time in the early stages, finishing the first lap of the course within ten seconds of Primoz Roglič's time, the Slovenian still only just ahead of his rivals in the early stages.
However, in the second half of the time trial the Slovenian was the most durable, catching up with his 90-second man Kasper Asgreen (Denmark) and then surging away as they approached the final on the Speedway.
In the end, Roglič had put an extra minute into his rivals on the hilly course, with Dumoulin a minute and one second behind in second and Dennis a minute and four seconds behind Roglič, surviving the finishes of Kung and Ganna to hang onto the podium.
The other Australian competitor was Richie Porte, who finished in 27th position, five minutes and 49 seconds behind the time of Roglič.
