Rossi faded in Australian GP as he was "slowest on the straight"

Rossi took the lead at the start of what was his 400th grand prix appearance from fourth on the grid, but could only keep first place for three laps before he was overtaken by LCR's Cal Crutchlow and several others in quick succession.

The 40-year-old was part of the group fighting for fourth, which became third after Maverick Vinales's last-lap crash, but he was only able to salvage eighth.

While Rossi said this race was better than Motegi, where he struggled for pace before crashing out, but was powerless to stop others from continuing to overtake him as he was consistently "not strong enough" over a lap.

"[It] was a great start, very good way to celebrate my 400th grand prix, to stay a little bit in front," Rossi said.

"At the end for sure the result is not fantastic, but I was not so far from [Jack] Miller, who arrived on the podium.

"I was able to ride in a better way, I was more competitive compared to last weekend. Anyway, we need more, we need to be stronger.

"The problem is, every lap I lost one position on the straight.

"We were a big group, but if I am not able to resist, or re-overtake during the lap, in the next lap the guy behind overtook me another time because I was for sure slowest on the straight of all the group.

"Unfortunately in some places I was not strong enough every lap to recover. At the end, I tried to ride smooth and not lose [too much] because I had other bikes behind."

Rossi added that having rear grip problems has been the "theme of the second half of the season" and that he is yet to find a solution to it.

"Here we found a good balance of the bike and in braking and entering corners I was very well placed with the front [end].

"But we lacked a bit of grip at the rear, which is the theme of the second half of the season, which for the moment we can't solve.

"We have to think about this and we have to try to improve."