The Australian's first victory for INEOS Grenadiers was also his first since taking the TT world title in Yorkshire in 2019.
One of the earlier starters down the ramp, Dennis set a new benchmark when he reached the finish, five seconds up on rival Remi Cavagna (Deceuninck-Quick-Step), and he was able to occupy the hot seat for the rest of the stage.
Success on roads local to his home, and with family and friends cheering him on, made it all the more special for Dennis, who hadn't claimed a TT win for 546 days prior to his success in Banyoles.
"I’m relieved! It’s been a long time between drinks if I’m completely honest," said Dennis. "It’s been a tough little road but it’s really great to be back on that top step. It’s amazing – the team have always supported and believed in the fact that I can be back on that top step. It’s just amazing to be back here."
The two-time world champion against the clock has mostly been finishing behind very strong opposition, with the likes of Remco Evenepoel and current world champion Filippo Ganna denying him victories in 2020. He was sixth in his most recent time trial at Paris-Nice, after which he described himself as getting older but still having more to give when it came to his cycling.
"It means a lot," said Dennis. "It’s my first victory with the INEOS Grenadiers and my first victory since Yorkshire Worlds. It’s been a pretty tough sort of year and a half of seconds, thirds or even being out of the top 10 sometimes.
"I've taken the actual feeling of winning for granted in the past but I definitely won't from now on.
"It’s something I’ve been trying to work on every day. It’s not getting any easier with all these young guys, so I’m making the most of this win at Volta a Catalunya. I train on these roads a lot and there are a lot of friends down here to cheer me on. It’s great to do it in front of them."
Dennis lost time on the opening stage and won't move into the leader's jersey, with 2020 Giro revelation Joao Almeida (Deceuninck-QuickStep) moving into the top overall position just a fraction of a second ahead of Brandon McNulty (UAE Team Emirates), with the top seven riders all within 10 seconds.
Dennis' teammates populated the top-15 on the stage and INEOS Grenadiers will go in with Richie Porte, Adam Yates, Geraint Thomas and Jonathan Castroviejo all in a good position while Richard Carapaz lurks in the wings, 52 seconds behind Almeida.
"For me I’m just the donkey if I’m honest with you," said Dennis of his role within the squad. "I’m the one that helps out, and it’s amazing that we’ve got the cards to play with the two Richies, G and Yatesy as well. It’s not going to get any easier from here – we’ve got Vallter 2000. Yesterday was the 'flat' stage and you saw how that was with Movistar when they lit it up. It’s good that we’ve got options."
Richie Porte rode a strong race to finish sixth on the day, the Tasmanian shaking off the effects of a nasty crash during Paris-Nice to display some ominous form ahead of the big mountain tests that await on Stages 3 and 4.