Christian Horner predicts that Mercedes have used a large portion of their Formula 1 development budget to introduce the "B-spec" W14 upgrades.
Having kept faith with the zero sidepods concept at the start of the season, Mercedes quickly abandoned this in favour for a more conventional design, which was finally introduced in Monaco.
At its first outing at a conventional, non-street track, the upgraded W14 proved to be the closest challenger to the all-conquering RB19, although Lewis Hamilton still finished 24 seconds behind Max Verstappen.
And it is clear to Horner that Mercedes have improved - although he pointed out that the gap at the end of the race was similar to in the 2023 season-opener in Bahrain.
Viewed by others:
"For sure they’ve made a step, they’ve introduced pretty much a B-spec car," Horner told media, including RacingNews365.com.
"They must have used a significant proportion of their development budget on that, and when look at the gap at the end of the race, it's very similar to where it was in Bahrain.
"All that's happening is the running order behind us seems to vary from race to race. It was Fernando [Alonso in Monaco], Mercedes [in Spain] and it'll be interesting to see how that plays out over the next few races."
Across the seven races up to and including the Spanish Grand Prix, Aston Martin have finished as the highest non-Red Bull on four occasions, Mercedes twice and Ferrari just once in Azerbaijan.
In Sakhir, Alonso was third and 38.7s behind race winner Max Verstappen with Ferrari and Mercedes nearly 50 seconds behind. In Spain, Hamilton finished 24 seconds behind the World Champion with Ferrari 45s down and Aston over a minute in their worst showing of the season.
Focusing on 2024
With Red Bull set to claim both championships once again in 2023, attention will soon be turned to the 2024 RB20 machine.
However, the Aerodynamic Testing Restriction (ATR) rules mean less development time is permitted at just 70% for the reigning Constructors' champions, before the further deduction of 10% for breaking the cost cap.
Horner says the team are balancing between developing the RB19 and ensuring they can get ahead with next year's car.
"We're strategically using the ATR because we have to balance it for this year and for next year with the development that is currently going on," he explained.
"The team are doing an incredible job being extremely efficient, we've very subtly developed the car since Bahrain.
"We've seen others bring significant upgrades now and the margin has been pretty much the same from where it was in Bahrain.
"That's hugely encouraging to everybody in Milton Keynes, who are doing an outstanding job at the moment."
Balve Bains is joined by RacingNews365.com Editorial Director Dieter Rencken and Asia Correspondent Michael Butterworth to ask if Mattia Binotto could really join Alpine, what Pirelli's new tyres are about and the latest on the Red Bull-Ford partnership!