Ferrari driver Massa has scored 49 points this season
By Andrew Benson
BBC Sport at the Circuit de Catalunya
Ferrari are to launch an investigation into Felipe Massa's performance following his continuing struggles alongside team-mate Fernando Alonso.
The Spanish Grand Prix was the fourth consecutive race at which the Brazilian has been well off Alonso's pace.
Team principal Stefano Domenicali said: "We have to make sure the car is one he feels confident driving. For the first time this weekend it was not the case.
"It is important to go back and see what we have done around Felipe's car."
Massa matched Alonso for pace at the first race of the season in Bahrain, which Alonso won from his team-mate.
But since then Massa has been several 10ths of a second behind the double world champion, who is rapidly emerging as Ferrari's de facto number one driver.
Alonso delighted with 'perfect' race (UK users only)
The 29-year-old said he did not understand why he was struggling to keep pace.
"Fernando is a very good driver but something has happened to me," Massa said.
"Something is not going like I want, so I can't do the lap time or drive the car like I want.
"This is something that we need to understand, and improve.
"It looks like something is not working out to give the grip. This is something that we need to understand, but I'm sure we will."
Until Spain, Ferrari's car was the second fastest in Formula 1 behind Red Bull, but the Italian team slipped behind McLaren on competitiveness in Barcelona.
Alonso and Domenicali both said the team were lacking aerodynamic downforce
And Domenicali admitted that while Massa had been complaining about the performance of his car, that had also been the case with Alonso.
"Felipe started to complain about the level of grip of the car from the beginning and that never happened (before)," Domenicali commented.
"To be honest, Fernando was also saying this."
Alonso is second in the championship, three points behind leader Jenson Button of McLaren, with Massa down in seventh, 21 points adrift.
Alonso lost points in the second race of the season in Australia because, after catching Massa following an early spin, he was unable to pass the Brazilian.
Alonso also spent the Malaysian GP stuck behind his team-mate despite being faster than him, and controversially passed him on the way into the pits in China to avoid the same thing happening for the third race in succession.
But Domenicali said it was too early to make Alonso the number one driver to ensure his title chances
Alonso added: "I'm happy with this position [in the championship], but as I said before, we need four or five podiums in a row.
"With one podium and then another three races with mistakes there is not enough to win the championship,
"But I think we understand, we know the problems, we know the mistakes we made at the beginning of the championship and we arrived in Barcelona with a very good approach, super Ferrari team.
"This weekend [we made] no mistakes at all: preparing for qualifying in practice in a good way, at the maximum of our potential in qualifying and a very solid race.
"Sometimes we know that we will be third, sometimes we know we will be fifth, sometimes we can maybe win the race, but we need to do our maximum and today or this weekend all the Ferrari team did the maximum so we are extremely happy with our job.
"There is a very aggressive plan of developing the car with some good gains and good improvements to come in the next races, so we are very optimistic on that.
"The championship is long. There will be some circuits where we will be closer to Red Bull and some circuits like this weekend where we know it's going to be more difficult.
"But overall, for the 19 races, I think we have a package, a car that can fight for the world championship which is the main goal."