Mika Kallio made an instant impact during his very first hour as a factory Ducati MotoGP rider, in place of 2007 world champion Casey Stoner, at Brno on Friday.

Promoted to the Ducati Marlboro squad for the next three races while Stoner seeks treatment for his mystery illness, Kallio - who has finished a best of eighth so far in his rookie year - ran fifth for much of the session, before being bumped back to seventh in the final minute.

Although 1.7sec behind fastest man Jorge Lorenzo at the end of the session, Kallio - who has brought his chief engineer and telemetry engineer with him from the satellite Pramac team - lapped just 0.718sec behind third placed Dani Pedrosa (Repsol Honda).

Most significantly, the young Finn occupied Stoner's usual place as the leading Ducati rider, with full time factory rider Nicky Hayden the next best Desmosedici in twelfth place and half a second behind the #36.

"It has been a really exciting day for me and to wear the famous red colours of Ducati Marlboro Team for the first time was a great honour, although once I got out on track I wasn't thinking about what I was wearing!" he smiled.

"We started out with my setting from Donington on one bike and something similar to what Casey ran here last year on the other, with a few changes to suit my preferences. Both settings had different strengths but the same weakness, which was a lack of rear grip on the left side.

"It was the same problem with both the softer and harder tyre so we're a little confused about what is causing it at the moment, but we'll sit down this evening and work out a plan for tomorrow.

"They tell me the bike is virtually the same as my satellite machine but I can't help but feel it has a little extra!" he revealed. "Usually I struggle a little on the first day because even though I know the circuits I am riding them all for the first time on a MotoGP bike this year so to finish seventh today, with such a small gap to third place, is really positive."

Hayden admits he'll need to do 'a lot better tomorrow' - but felt he's heading in the right direction.

"Twelfth place isn't a particularly great start for us but we made progress with every run and I was getting faster and faster as the session went on so I can't say it was a complete disaster," began Nicky.

"Obviously we are going to have to do a lot better tomorrow but I think we've found a bit of a direction with the bike. We're struggling a little with the rear on corner entry, it feels really loose, so our main target is to fix this problem.

"I was pushing the front a lot early in the session so we made a change, got it steering a lot better and we were able to progress from there. Now we need to work on the rear and try to make a big step forward tomorrow."