Red Bull: China proves progress, speed flaw
Christian Horner believes his Red Bull team made a step forward in understanding its chassis in Formula 1's Chinese Grand Prix, but that top speed is now its main weakness.
Red Bull struggled to find a good balance in its car in both Australia and Bahrain before a breakthrough in the post-Bahrain Grand Prix test helped it understand its direction.
Max Verstappen then split the two Ferraris to take fourth place in the Chinese Grand Prix.
Horner believes the result proves it is on the right track, pointing to Red Bull's strength in the technical, slower-speed first and second sector compared to the third sector which includes the ultra-long back straight.
"We have made a step forward from Bahrain and we were definitely more competitive this weekend," said Horner.
"When you look on the overlays, particular sector one and sector two, we are in good shape.
"In sector three we still have some work to do, but we have some upgrades and so on coming soon that will help with that.
"So generally on that side, a positive weekend."
The long straight in the third sector, which measures at 1.2 kilometres (0.75 miles), requires strong performance from the engine.
"I think they are making progress with it," he said. "There is stuff in the pipeline that will certainly help but others aren't standing still.
"It is all about evolution. Our goal this year has been all about closing the gap to Mercedes and Ferrari and we are doing that.
"We split the Ferraris and were are certainly closer on pace to Mercedes. There will be a concertina effect that will happen between now and the halfway point of the year."
Horner added that fourth was the maximum Red Bull could extract from the Chinese GP and that it could only beat one of the two Ferraris by using a two-stop strategy.
"I don't think we had a faster car than Ferrari, so our best way of beating at least one of their cars was going on to the two stop," said Horner.
"That then sparked some discussion between Sebastian [Vettel] and his pit wall as to whether or not they were going to stop at all, but in the end they covered, and Mercedes had to cover him."