'Difficult day' leaves Rossi 18th
Valentino Rossi suffered his worst start to a MotoGP weekend this season with 18th place, and slowest Yamaha, after Friday practice for his home Italian round.
16th fastest on hard tyres, Rossi switched to a new soft rear for a time attack in the closing minutes of the afternoon session, but lost further ground relative to his opponents.
Nonetheless, lap times were close, with Rossi within one-second of Pramac Ducati rookie Francesco Bagnaia's pace-setting lap.
Valentino Rossi suffered his worst start to a MotoGP weekend this season with 18th place, and slowest Yamaha, after Friday practice for his home Italian round.
16th fastest on hard tyres, Rossi switched to a new soft rear for a time attack in the closing minutes of the afternoon session, but lost further ground relative to his opponents.
Nonetheless, lap times were close, with Rossi within one-second of Pramac Ducati rookie Francesco Bagnaia's pace-setting lap.
The Doctor was also less than half-a-second from another VR46 protegee, Franco Morbidelli (Petronas Yamaha), who currently holds the final top ten place for direct access to Qualifying 2.
Meanwhile rookie Fabio Quartararo again impressed with second on the timesheets (+0.046s) for the satellite Sepang team, with Rossi's team-mate Maverick Vinales claiming a Friday fifth (+0.241s) but warning he is 'struggling everywhere'.
"It was a difficult day, I expected to be more competitive, but already from this morning I wasn't very fast," said Rossi, twelfth in FP1 (+0.798s).
"I wasn't able to ride in a very good way and I am slower than last year. We are all very close and for this reason my position is very bad.
"This afternoon we tried the hard tyres etc, but anyway the pace isn't fantastic.
"I am slow in the corner. I don't have the pace. I need to be faster. Today we suffered, so tomorrow we will try to change something.
"Now we will check all the data and see what we can do."
While Rossi had put a brave face on the M1's top speed deficit prior to the weekend, emphasising Mugello's many flowing corners, the fastest straight of the season proved a punishing experience for the Yamahas.
Rossi was quickest of the M1 quartet through the speed trap this afternoon at 340.4km/h (211.5mph), but it was only good enough for the 16th highest speed, 9.5km/h behind Andrea Dovizioso's Ducati.
The other Yamahas failed to break 338km/h, with Morbidelli slowest of the 23-rider field on 332.9km/h.
The average top-speed charts (top five speeds for each rider, to reduce the significance of a one-lap tow) told a similar tale, with Michele Pirro quickest for Ducati on 347.7km/h and Rossi top Yamaha in 15th on 338.8km/h.
To try and coax more top speed, all four Yamahas ran the older fairing design due to its lower drag levels (but less downforce).
While Rossi's predicament wasn't helped by the lack of top speed, he admitted: "We need to improve in other areas than just top speed, because anyway the other Yamahas are quite fast."
Although FP2 proved to be Rossi's worst session, team director Massimo Meregalli had been more shocked by FP1, when both factory riders were outside the top eleven.
“We already assumed this weekend would start with some difficulties here in Mugello considering the long straight, but we didn't expect the struggles we experienced in FP1," Meregalli said.
"During FP2 the situation became more normal again, apart from Valentino's P18, so we need to find out what happened there. We have been fast in Sector 1-3 and we lost time where we foresaw [the straight].
"I expect that it will be a long night for our engineers to analyse the data and prepare some solutions so we can improve our performance at both sides of the garage for tomorrow's FP3 and have both riders in Q2.”
Rossi qualified on pole position at Mugello last season and went on to finish third in the race.
"Now it's difficult to say because I'm really far back, but it's just Friday so we have to try to work in all the areas and be more competitive," Rossi said of his podium chances on Sunday.
The Italian is currently fourth in the world championship, 23 points from Marc Marquez (Honda). Marquez was sixth quickest on Friday, despite staying on the same soft rear tyre for the whole of the afternoon session.