Red Bull has “definitely" closed the gap to Formula 1 rivals Mercedes and Ferrari heading into the 2019 season, according to team boss Christian Horner. 

The Milton-Keynes squad has been left optimistic by a promising pre-season showing from new engine suppliers Honda, with Horner claiming the Japanese power unit manufacturer has provided Red Bull with its best-ever installation. 

Drivers Max Verstappen and Pierre Gasly have also been encouraged by the steps made by Honda over the winter and Horner believes the gains will successfully reduce some of the deficit to F1’s leading two teams. 

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“It's clear Ferrari after the second test look very strong,” Horner told Sky Sports. 

“Mercedes are going to be there or thereabouts, they're the reigning world champions so they're not going to be slacking.

“I think we have definitely closed that gap. We will see not just in Melbourne, because that's a little bit of a unique track, but look over the first three races and then ask me again then how we're faring.” 

Horner, who described Honda’s 2019 power unit as a “thing of beauty”, said Red Bull’s decision to break from long-term engine partners Renault in favour of a switch to Honda has energised the whole team, including design guru Adrian Newey. 

"The engine change has stimulated the whole team - and particularly Adrian," Horner explained. 

"He sees that the engine is now getting closer and closer to the performance of the front-running teams. That's really motivated him and he's working very hard with all the guys and girls back in Milton Keynes.

"Hopefully we can look forward to a good season. Our job is to close that gap to Ferrari and Mercedes."