Ferrari team principal Mattia Binotto has revealed his concern at the number of upgrades being made by Red Bull despite the budget cap restrictions.
Max Verstappen won the inaugural Miami Grand Prix after jumping both Charles Leclerc and Carlos Sainz during the 57-lap event, cutting the championship deficit to the Monégasque to just 19 points.
But Red Bull has brought incremental upgrades throughout the season so far, compared to Ferrari which is working to a different strategy.
Teams face the challenge of developing their new generation of cars this season within budget cap restrictions, with a maximum spend permitted of $140million, excluding certain factors such as driver salaries.
On whether Red Bull's rapid development was a concern, Binotto explained: "I would say, at first, it is not because I don’t think that the difference is huge. It is a matter of a maximum of a couple of tenths in the race.
"We should not forget that we locked out the front row, so in quali we had a better performance compared to the Red Bull.
“So overall, on a weekend, I don’t think that there is much difference between the Red Bull and the Ferrari.
But highlighting where he was worried, Binotto added: "It is how much they are developing considering the budget cap.
"That is certainly a concern I have got but more than a concern, maybe it is a hope because at some stage they will need to stop.”
Ferrari can't upgrade each race - Binotto
F1 introduced new regulations this season to provide more exciting racing but as with the beginning of any ruleset, development through the season will be just as important as getting off to a quick start.
Yet insisting the Scuderia cannot replicate Red Bull's upgrade pattern thus far, Binotto said: “We do not have the money to bring upgrades to each single race, I think that is as simple as that.
“Not because of reliability, but because of the budget cap. So we need to somehow focus the developments on when we believe it is the right moment and the right spending.”
Additional reporting by Ian Parkes