LONDON, England - McLaren says it has an aggressive development programme for its cars and intends to close the gap to Mercedes by the first European race of the 2014 Formula 1 season in May.That's the claim made on Wednesday (March 18) by racing director Eric Boullier.McLaren's Kevin Magnussen and Jenson Button finished second and third in the March 16's season-opener in Melbourne that was won comfortably by Mercedes' Nico Rosberg.PLAYING CATCH-UPButton said the Mercedes cars about a second a lap quicker than the rest but Boullier, who joined the team in 2014 from Lotus, felt the gap was less. Boullier said: "It's true that Mercedes and Williams have some pace. Maybe half to three-quarters of a second quicker than the rest of the field."We focused a lot of our testing on building a solid and reliable car because we believed - and Australia confirmed our strategy - that reliability was the key to taking big points at the beginning of the season. Now... we are pushing very aggressively on performance development - we clearly need to close the gap to Mercedes and some others."Our target is to catch up by Barcelona (May 11) and build up over the first few races in Europe."The Spanish GP will be the fifth of the season's 19 races.The podium positions in Australia were McLaren's first since 2012 with the team suffering its worst season in decades.Boullier warned that some other teams that had under-performed in Melbourne would be very fast when they resolved their problems.2013 champion team Red Bull's driver Daniel Ricciardo disqualified from second place in his home GP for exceeding the fuel-flow rate; team mate and quadruple champion Sebastian Vettel lasted for only three laps.Red Bull's engine provider Renault had a torrid time in pre-season testing with Red Bull arriving in Australia without having completed a race simulation.Ferrari also recognised the team had work to do after Fernando Alonso and Kimi Raikkonen finished fourth and seventh respectively. Technical director James Allison told the Ferrari website: "We can take some satisfaction from the reliability shown by the F14T but it is clear we have our work cut out to improve our cars to compete on equal terms with the Mercedes team. "We need to work further on braking stability and straight-line speed... we intend to fight our way back up the grid."Stay with Wheels24 for the 2014 F1 season – fresh reports every day.