Fastest with an all-time unofficial lap record at Sepang, Jorge Lorenzo plummeted down the timesheets to a shock 22nd out of 24 riders on the final day of the inaugural Thailand MotoGP test.

The Ducati star's Buriram woes also prompted a recall of the 2017 machine, believed to have been pulled from Danilo Petrucci's garage ("I have only one bike today") for another back-to-back comparison with the new GP18.

Unfortunately for Lorenzo there was no clear favourite and he is already talking of patience in the opening rounds until a 'mix' of the old and new bikes can arrive.

"On the last day in Sepang I was in first position and here I'm 22nd. But we cannot take this as a conclusion because all the riders tried to make a quick lap time in the morning and I was going with old tyres," said Lorenzo, who was one place behind MotoGP newcomer Hafizh Syahrin on the Sunday timesheets.

"We are much better than this 22nd position. Probably we are not in the top three, but also we are not in the last three."

But the triple MotoGP champion admitted:

"Today and also the first day have been difficult. Not so much confidence, very far from the top riders. So that's why, in a difficult situation, we decided to try again the old bike.

"It has been important to try again the old bike that still has some points that are better than the new one, but also some points worse.

"The problem is that for Qatar it is going to be difficult to make a mix, but if I have to chose at the moment and take a conclusion I think with the new bike we have a bigger potential.

"We have to be patient probably in the first races, try to get the best results that we can. Probably Qatar will be much better than here - like we were in Sepang - and wait for some kind of mix as soon as possible to be more competitive."

Unwilling to provide exact details of what he likes and dislikes about the old and new bikes, Lorenzo did confirm it is chassis rather than engine related.

"Yeah I cannot speak very precisely, but in general the new chassis still has some negative points that I don't like so much."

And when asked if he will continue trying the old and new bikes in the final Qatar test, Lorenzo spoke of a lack of front freeling.

"Let's just see what the engineers can do in some days, something from the old bike into the new one and also work on the setting of the new bike, especially to feel more the front tyre that at this track I didn't feel anything. So let's see."

In terms of combined lap times over the three days, Lorenzo was 16th and 0.948s from Honda's Dani Pedrosa courtesy of a 1m 30.729s on Saturday. His Sunday best was a 1m 31.627s.

Team-mate Andrea Dovizioso - seventh overall, but only 0.411s from Pedrosa - has no such reservations about the GP18.

"We didn't compare the GP17 and GP18. I think what we feel in Malaysia, it was clear [the GP18 is better], so I have no question mark about that."

Petrucci has been using one GP18 and one GP17, but concentrating on the newer bike as he also feels it is clearly better.

When Petrucci receives his second GP18 from Ducati, the GP17 thought to have been given to Lorenzo on Sunday will move across the Pramac garage to become Jack Miller's spare bike.

The Qatar test starts on March 1.