Manama - Former world champion Nico Rosberg believes Valtteri Bottas is seeking to "get under Lewis Hamilton's skin" and making a good job of it so far this season.
The 2016 champion, who beat his Mercedes team-mate Hamilton to take the title, said it was essential for Bottas to try to reduce the Briton's own confidence by chipping away at his supremacy to beat him.
"He is really trying to get under Lewis' skin at the moment," Rosberg told Sky Sports F1 ahead of qualifying on Saturday.
"He's giving everything and I think he's doing a good job. It's always small steps at a time and you've got to pull Lewis down from his high-flying confidence.
"He's doing that and then you start to see Lewis getting a few doubts and things like that. That's the way to go for him... And I think he's done a very good job over the winter to reset."
Bottas won the season-opening Australian Grand Prix earlier this month, but was outpaced by Hamilton in qualifying for the Bahrain Grand Prix on Saturday, the two Mercedes winding up third and fourth.
The Ferraris of new boy Charles Leclerc and four-time champion German Sebastian Vettel were first and second to lock out the front row of the grid.