Last updated on .From the section Formula 1

McLaren boss Martin Whitmarsh says he is "very frustrated" that the team have failed to convert a competitive car into a lead in both championships.

The team have made several operational errors in the first five races, with Lewis Hamilton unable to convert any of his three front-row starts into wins.

But Whitmarsh said he was "confident" those mistakes are now in the past.

"We should have had more success then we've had," he said. "I think in life, we all have moments of frustration."

Hamilton started the Malaysian Grand Prix on pole, but delays during two of his stops dropped him down the field and he finished third.

In Bahrain, wheel nut problems at two separate stops saw the 2008 world champion finish eighth after starting second.

Hamilton's season Australia: Started on pole but finished third after an unlucky break with the safety car.

Malaysia: Problems at two pit stops meant he lost a chunk of time, finishing third after starting on pole.

China: Qualified second but started seventh after a five-place grid penalty for a gearbox change.

Bahrain: Wheel nut problems during two stops saw him drop down the field and finish eighth after starting second.

Spain: Ran out of fuel in qualifying and was demoted to the back of the grid from pole.

Then, last time out in Spain, Hamilton ran out of fuel in qualifying after an operational error and was demoted from pole to the back of the grid.

Jenson Button, meanwhile, won the opening race of the season but a combination of driver errors and a struggle to make the Pirelli tyres work has halted his title charge.

"I'm very frustrated," added Whitmarsh. "We've got a reasonable car and two great drivers. Either could win drivers' championship and this team could win the constructors' title. We're in a strong position.

"We are confident the issues we have had so far have been dealt with and are in the past.

"I'm mindful that in the present, there are always new things that can come and bite you so we should not be complacent and say we've sorted everything.

"We've made a range of changes within the team in terms of processes and personnel to deal with some of the issues.

"Everyone in this company is mindful that a small human error on their part could draw some difficulty in any of the races that are left this season."

Hamilton fought back from last place to finish eighth in Spain but, despite his run of bad luck, the Briton is still only eight points off the lead of the drivers' championship.

"He's been unlucky this year," added Whitmarsh. "The last race was disappointing for the team, but Lewis should come away from there with very strong feelings about what he achieved this year.

"He has a car that is capable of being on pole, he has shown the speed and capability to be on pole and he's striving to greater levels of maturity then perhaps we've seen before.

"He's eight points away from the championship lead and he must consider himself a very strong candidate to winning Monaco and this world championship."

Hamilton, who won the Monaco Grand Prix in 2008, refused to be downbeat about his lacklustre start of the season.

"I'm not frustrated, this is the way racing goes sometimes," said Hamilton. "Of course we would love to have finished further up and we definitely need to improve.

"We have gone backwards a little bit in most of the races, but we are working to make sure that isn't the case any more."