Fernando Alonso says Renault must make improvements to counter Michael Schumacher's return to form.
Schumacher won back-to-back Grands Prix at Imola and the Nurburgring but Alonso wants to match him in front of his home fans at Sunday's Spanish race.
"We need to improve in all areas," said Alonso. "We now need something more to win than we currently have.
"I expect Barcelona will be a good race for us because we have always been quick there in testing."
World champion Alonso has not finished outside the top two in any of the five Grands Prix this season and holds a 13-point advantage over Ferrari's Schumacher at the top of the drivers' standings.
"We are closer to the lead and there is a definite improvement from the last race"
The 24-year-old has yet to savour success in his home country but believes he is favourite for Sunday's race despite growing pressure from the chasing pack.
"Michelin (tyres) have been in a dominant position in Barcelona over the last two years, so I'm really looking forward to winning that one," said Alonso.
"It's not a surprise that Ferrari are fighting, but I expect McLaren will arrive also.
"Honda are really strong in some races so there are four teams who have a chance to win and all four are strong and ready to fight."
McLaren's Kimi Raikkonen just missed out on a podium spot at the Nurburgring when he came in fourth.
But the team, who are third in the constructors' table with Raikkonen occupying the same spot in the drivers' standings, believe they are close to making a real impact on the championship race.
"We are closer to the lead and there is a definite improvement from the last race," said Raikkonen.
"We now have to continue our hard work so that we can perform better in Barcelona."
McLaren team boss Ron Dennis added: "We are very close with Renault and Ferrari.
"We will now look towards Barcelona which will be tough as it is back-to-back with Germany but we still intend to improve our competitiveness further."