Andrea Dovizioso feels he can challenge towards the front of the second row during qualifying for the Indianapolis Grand Prix after making substantial gains between the practice sessions.

The Italian, who is tipped to be confirmed as Valentino Rossi's replacement at Ducati as soon as next week, was considerably off the pace during the first practice session as he struggled with a 'green' circuit, but vaulted up the leaderboard in the second session to end up fourth best.

Pleased to slash three seconds off his best time, the Tech 3 Yamaha rider is already confident that he can prove similarly competitive in qualifying.

"I'm really happy with my rhythm this afternoon because this morning the track was unbelievable," he said. "There was absolutely no grip and it was very difficult to try and understand the feeling from the bike or where the limit was.

"I improved by more than three seconds from this morning so it shows how bad the conditions were. But we expected this because it's always like this here. The infield track we race on is not used during the whole year, so it's quite dirty. And yesterday's rain certainly would not have helped.

We made some good changes to the bike for the second session but we need to improve our pace again tomorrow. Ben was able to do some very consistent laps and he is the benchmark for Yamaha so far.

"I can look forward to tomorrow though with a lot of confidence and I'm sure I can be fighting to be on the second row at least. If we can find some more grip, particularly on corner entry, then we should be very competitive tomorrow."