Formula One manufacturer Renault needs two more races before providing a competitive engine again at the Monaco Grand Prix, according to chief technical officer Rob White.

Renault, which supplies engines to Red Bull and Toro Rosso, is under heavy pressure following a poor start to the season for both teams.

At last weekend’s Chinese GP, Red Bull driver Daniil Kvyat and Toro Rosso teenage driver Max Verstappen both retired with engine failures.

“We had a bad day at the office in China, and the consequences of that bear very heavily on everybody,” White said.

“It’s never good to cause trouble for the teams or the drivers.”

At the season-opener in Australia, Red Bull’s Daniel Ricciardo finished sixth and Kvyat failed to score points – well below expectations after Ricciardo won three races last season.

Both Red Bulls were lapped by race winner Sebastian Vettel’s Ferrari in Malaysia, after which owner Dietrich Mateschitz threatened to withdraw from F1 if Renault could not make engines more competitive.

At the Bahrain race, Ricciardo qualifeed seventh fastest and Kvyat 17th, while Toro Rosso’s Carlos Sainz Jr. – the son of the two-time world rally champion – was an encouraging ninth. Verstappen struggled and placed 15th.

White said Kvyat’s engine failure in Shanghai was more understandable, and a “counter-measure” has since been put into place, but acknowledged Verstappen’s setback took them by surprise because “we were absolutely not expecting such a thing at such a low mileage.”

White does not expect the problems to go away in Bahrain or at the following race in Spain in three weeks.

A late change of specification for Renault’s 2015 power unit has been a main contributing factor to the problems, and White hopes a major upgrade later in the season will pay dividends.