Following three days of pre-season testing, Alonso has suggested Max Verstappen will win a fourth title in 2024.
F1 last season endured a year of utter domination from Red Bull Racing and Verstappen, the latter winning 19 times, and his team twice more, in 22 races.
It was a record-shattering campaign that left many looking to 2024, hoping for a more competitive showing.
Based on what he saw in testing, Alonso doesn’t believe that will happen.
“I don’t have a crystal ball to know what the others are doing,” the two-time world champion began.
“Max is the world champion and Red Bull is dominating the sport. Also, the concept that they presented this year, it’s also a surprise.
“At the moment, we just have to watch them and see how they perform. I think 19 drivers in the paddock now will think that [they] will not win the championship.
“It happens 99 percent of the time in your career. This is a brutal sport.”
Alonso won two titles with Renault in 2005 and 2006 but last won a race in 2013.
Aston Martin made significant strides last season and proved Red Bull Racing’s nearest challenger in the early races, and Alonso arguably should have won in Monaco.
However, Aston’s challenge faded as the year went on, the Silverstone squad behind in the development race.
This year, it did not prove a standout performer in testing like a year ago, but it did do enough to suggest it will be a contender for podium positions.
“We went into this season really looking for a step over the winter, and wanted to make sure we did get an improvement, even though it’s an evolution of last year’s car,” said Dan Fallows, Aston Martin’s technical director.
“We have seen that step… So very pleased about that.
“I think the most important thing for us is where we go from here.
“We weren’t 100 percent pleased with what we achieved in our in-season development last year and we need to make sure we can compete at the top level in terms of in-season [development] as well.”
Aston Martin is thought to be battling to be the third-best team with Mercedes and McLaren.
As noted by Alonso, Red Bull Racing is tipped to dominate, with Ferrari expected to occupy a clear second spot beyond the Milton Keynes operation.
“In terms of drivability, the car is a lot better compared to last year,” said Ferrari’s Charles Leclerc.
“But last year after the test, it was very, very difficult to push into a direction, because we just didn’t know what the car was doing.
“We would get into a corner and we didn’t know whether we will have extreme oversteer or extreme understeer, which was a big problem.
“This year, the car is not like that, which is a better starting point.
“However, my initial feeling is that Red Bull unfortunately remains quite a bit ahead. They have done very impressive lap times.”
Leclerc’s assessment comes despite Ferrari topping two of the three days of pre-season running, and finds support from McLaren’s Adrea Stella.
“There’s one car that seems to have found a big step,” the Italian said following the second day of testing.
“Unfortunately, [it’s] the car that was already the quickest last year.”
The 2024 F1 season begins with the Bahrain Grand Prix from Thursday, with Free Practice 1 set to begin at 22:30 AEDT.