Jean-Eric Vergne believes keeping the "tension" to a minimum will be key to a successful working relationship between himself and Daniel Ricciardo.
The stakes are likely to be high at Toro Rosso this season after Red Bull Racing team owner Dietrich Mateschitz made it clear that they are likely to promote one of their junior drivers to race alongside Sebastian Vettel should Mark Webber decide to call it quits at the end of this year.
With a potential Red Bull seat on offer, it could lead to tension between rookies Vergne and Ricciardo this campaign.
However, the Frenchman warns that they can't afford to allow other aspects to ruin their relationship at STR.
"There was not too much tension when climbing into the car [during the test at Jerez]," he told RMC Radio.
"You have to forget about all those different aspects when you think about the work you need to do. We had four good days of testing, and the engineers are working now for the next test in Barcelona at the end of the month.
"There is a competition with my team-mate but, at the same time, we can't [let it] go in the wrong direction.
"You always want to beat everybody, but my team-mate is also the only other person who is driving the same car as I."