The presence of world champion Peter Sagan (Tinkoff-Saxo), Tom Boonen (Etixx-QuickStep) and a host of other big-name riders meant that Guardini was overlooked in the pre-race build-up. However, he left all his rivals several bike lengths behind when he kicked in the final 150 metres.
"In the last 250 I was on Bennati's [wheel] and saw that Sagan pulled him for a long time on the front. At 150 I heard my name called out by the race announcer and jumped. I had the legs to make a really powerful sprint," he explained in his post-race press conference.
Guardini admitted that he suffered in the heat but used his suffering as motivation.
"I think this is the hottest day of my career and was for most other riders too," he said. "When I saw the other riders I thought that I while maybe I was suffering, perhaps the other riders were suffering more than me."
Boonen managed to take second on the line, edging past Daniele Bennati, who had been given the role of sprinter and a huge lead out by Peter Sagan.
Boonen only had Lukasz Wisniowski with him in the sprint and made an effort to get on Sagan's wheel only to quickly realise he was leading out Bennati.
"He (Sagan) came to the front way too early. And I only have two guys here for the sprint," he lamented. "I was hoping that somebody would come in between us, but obviously everybody just let us do our thing and then Guardini accelerated and at that point I was cooked."
Bennati revealed that Sagan had decided he did not want the responsibility of sprinting for victory on his race debut in the rainbow jersey, preferring to lead out the veteran Italian.
"I was fast when I was young but I'm older now and not fast anymore. There was nothing I could do against a super fast finisher like Guardini," Bennati said. "It's a pity that Boonen passed me on the line because the team and Sagan did a great job.
"Sagan said he'd work for me with about 70km to go but that only made me feel under pressure because he's the new world champion but he did a great job. He could have sprinted himself in truth. I'm sure he'll try to win in the next few days. He's really happy to be world champion and we're proud to have him as world champion in the team."
Thanks to the time bonuses of 10, 6 and 4 seconds awarded at the finish, Guardini leads the overall classification by four seconds. He will wear the leader's red jersey during Friday's second stage from the Yas Formula One motor racing circuit to the Yas Mall. He will be the rider to beat in the expected bunch sprint finish.