The Silverstone-based team owned by Canadian billionaire Lawrence Stroll ended last year seventh overall but are now third, after being second for a while, behind runaway leaders Red Bull and former champions Mercedes.
Fernando Alonso (41), the double world champion who jumped from Renault-owned Alpine to Aston Martin at the end of last year, has stood on the podium six times in eight races with two second places.
The Spaniard is best of the rest, behind Red Bull's dominant leader Max Verstappen (25) and Sergio Perez (33) in the drivers' standings.
Alpine, who finished fourth overall last year and had hoped to close the gap on the top three, are fifth with French pair Esteban Ocon (26) and Pierre Gasly (27) ninth and 10th.
"I think it was a reality check for Mercedes, Ferrari, us," Rossi told reporters at Alpine's Enstone factory after a strategy presentation.
"For everyone. For the whole sport.
"We were comfortable thinking we were on the rise, and everyone else was, and suddenly there’s a guy leapfrogging all of us."
SHAKE UP
Aston Martin have recruited key technical personnel from Red Bull - notably technical director Dan Fallows - and engine providers Mercedes, but Rossi suggested they had also shaken up accepted ways of thinking.
"It’s an industry that has been doing more or less the same thing for so long that its become a norm that it takes that much time to get there," said the Frenchman. "It’s true for everything, for road cars.
"They (Aston) have changed a couple of things, faster, differently, they took a bit more risk and it paid off."
Rossi said Alpine needed to try and emulate that by speeding up processes to get upgraded parts on the car, taking more risks and using their strength as a works team.
Alpine last year embarked on a 100-race plan, the equivalent of four or five years, to get to the point of fighting for titles.
"People start scratching their heads a bit more thinking that maybe we’re being a bit too conservative here, maybe we’re doing too many validations, maybe we can shorten the process here and there," said Rossi.
"You realise that over time you’ve built so many of those extra cautious steps because you address the problem one day and say to yourself 'OK, next time we do this all the time'.
"Now you look at it and with hindsight perhaps this is not necessary any more."
"So we are revisiting a lot of things."
