LONDON, England - Lotus F1 boss Eric Boullier has applauded his team's emergence as a 2013 title contender and signalled upgrades to increase the Renault-powered outfit's competitiveness ahead of the Spanish Grand Prix in May 2013.Reflecting on the points earned in the four “flyaway” season-opening grands prix- Australia, Malaysia, China and Bahrain - Boullier said the team was confident it could maintain the big overall improvement in form which has lifted it to the front of the field (see points table below).'WE ARE FIGHTING'Boullier said: "It is always difficult to maintain momentum, but we are fighting with the best. The challenge is having development potential to push on."Early form has made Lotus 2013's the most improved team in year-on-year comparisons. Kimi Raikkonen has delivered three podium finishes, including victory in Australia, and the team has scored 36 points more than it did in the same four races in 2012.Raikkonen has improved his tally by 33 points to emerge as a serious contender for the Drivers' World title and Boullier has promised that the early season dazzle would continue as the team seeks to end Red Bull's three-year reign at the top.Lotus is not the only team enjoying an improved points tally, Ferrari and Mercedes have shown big gains in 2013 with the former's Brazilian driver Felipe Massa delivering 28 more points in 2013 than in 2012 - a major part of the team's improvement by 32 points.Mercedes, with Briton Lewis Hamilton showing the way, has improved by 27 but McLaren, the team he left, has dropped 69 points over four races and needs a sensational return from the upgrades promised in Spain.F1 top teams points:1) Red Bull - 1092) Lotus - 933) Ferrari - 774) Mercedes - 64See full team standings here Stay with Wheels24 for the 2013 Formula 1 season – fresh reports every day.