But Dennis faced a tough challenge both from power TT riders and general classification contenders, particularly his team-mates Filippo Ganna, Geraint Thomas, Richie Porte.
The prologue stage of the 2021 Tour de Romandie was a demanding course, with an out-and-back start followed by a sharp 700m climb with a six per cent average gradient.
Speaking after his second TT victory of the year, Dennis said: “It was full gas… Then full gas even more! It was quite tricky to pace it, because there’s still a minute and a half uphill and there’s no way to get the extra speed unless you’ve got the power. That last 700-800m really hurt.
“I thought when I hit the climb that I had gone too slow, but on the climb it didn’t feel like that, the last 400m seemed to go on forever. It was a tough little finish.
“It was a great day with first, second and third with G and Richie on the podium as well, it was perfect for us.”
Ineos Grenadiers dominated the stage, with Dennis taking the win and the overall lead, while Geraint Thomas and Porte filled the podium spots, both nine seconds behind.
The team are now in a strong position for the overall battle heading into the first road stage, as they will hope to follow-up on their clean sweep in the Volta a Catalunya, where Adam Yates took victory with Porte and Thomas on the podium.
On his TT win, Dennis said: “I knew I had to go out hard to stay in contention with riders like Filippo and the power guys and then hope that I could perform on the climb a little bit better than them. My tactic was to minimise the time on the flat and hit the hill as hard as I could. I didn’t lose too much time to G and Richie on the climb and I’m pretty happy with my form.
“It’s given me a lot of confidence for the final stage and shown I can do this in such a short time trial, with pure power, I think it’s going to be a good week – especially after the last race when I was climbing pretty well, but plenty of work to do yet.”
He added: “I’d like to keep the leader’s jersey for as long as possible, but let’s see how it goes with the big mountains on Saturday then the final day with the TT, but I think there’s plenty of work for me to do for Richie and G.”