MANAMA, March 10 — Formula One champions Mercedes were the talk of pre-season testing in Bahrain today after turning up with a radically revised car that caught the eye and raised hackles at rivals Red Bull.

The new-look W13 car featured dramatically narrower sidepods, with Formula One’s motorsport managing director Ross Brawn saying the concept was impressive and a "very extreme interpretation of the regulation” that had not been anticipated.

"Inevitably, there’s going to be a lot of debate about their interpretation. That’s what happens with new regulations,” he told F1 TV.

"However hard you try to close off all the options, and believe me we closed off hundreds of them, the innovation in Formula One is always extreme.”

Red Bull team boss Christian Horner was quoted by Germany’s Auto Motor und Sport as saying the Mercedes violated the "spirit” of the regulations.

The team said the quotes were incorrect.

Horner, whose Dutch driver Max Verstappen beat Mercedes’ seven times champion Lewis Hamilton to the title last year in a controversial final showdown, later told Sky Sports television he had "not paid a great deal of attention” to the Mercedes.

"It’s obviously a fairly different concept, but that’s for the designer guys and aerodynamicists to get into,” added the Briton.

Ferrari’s Charles Leclerc topped the timesheets at the lunch break at the Sakhir circuit, with Sergio Perez fourth for Red Bull and Hamilton fifth fastest. — Reuters