MotoGP rookie Marc Marquez and record breaker Valentino Rossi 'raced' for a handful of laps during Thursday's final day of testing at Sepang.

The usual reaction when two top riders meet on track in testing is for the person ahead to back off, to avoid giving away their strengths and weaknesses.

Instead Rossi and Marquez rode flat out, with each taking turns to lead.

At the conclusion of testing, reigning Moto2 champion Marquez was the first to speak about the encounter, which gave him a valuable insight into the riding technique of the seven time MotoGP champion.

"I was quite happy," began the young Repsol Honda rider. "In the beginning it was a little bit strange [to be riding with Rossi]. But it was good because I saw a rider with a lot of experience and I learnt many things in just three laps.

"I saw that my riding style in some corners - I didn't have the right line or I ride the bike more 'complicated' than him. For example he did some corners easier and faster. My line was a little more on the limit, but slower. So I learnt meant things. Then I did a few laps in front of him. It was quite funny!"

The high-speed formation ride also seemed to be a highlight of Rossi's day. During his own media debrief later that evening, the Italian broke into a broad smile as he recalled the exchange.

"Very funny to watch from behind," Rossi said of Marquez. "First of all we exited the pits together and I saw him wait and I went in front. It was good because I stayed in front for three laps and then I slowed down - but then he went in front. So you each give some information, but you also take something.

"I enjoyed it a lot because his riding style is very spectacular. F**k, he rides very hard! I liked it a lot. I said to him yesterday, 'this year we can fight and we can enjoy'. With Lorenzo or Pedrosa it is more difficult. When you are behind them [in testing] always they slow down - and me also, when they are behind me. But with Marquez it was funny!"

Rossi, returning to Yamaha after two tough seasons at Ducati, especially enjoyed seeing the Spaniard's spectacular riding style at such close range.

"For me Marquez rides very similar to Stoner, also because the Honda is like this," explained Rossi.

"Marquez is very spectacular. The bike moves, slides and he always touches his elbow on the track. He is very good and already so fast.

"It is particular, a strange riding style. Something new. Me and Jorge, our riding style is more 'classic'. Marquez is something different.

"Okay the Honda is different. But this thing where he touches his elbow in every corner is very good - especially for the people that watch the races."

Marquez and Rossi finished the final day of Sepang testing in second and fourth respectively.

Rossi has long praised the potential of Marquez, even before the newly 20-year-old had turned a wheel in MotoGP.

"I expect - and said three or four months ago - that Marquez can fight for victory from the start of the season," Rossi commented at the first Sepang test.