As commented by the 3-time world champion, Piquet Jr.'s performances at Circuit de Catalunya in both qualifying and race were better than Alonso's because the Brazilian's car was not fitted with the newly-developed rear diffuser.
According to Piquet Sr., the aforementioned features is reportedly bringing the Renault R29 an extra two tenths of a second. As Nelsinho lapped the Montmelo circuit approximately one tenth of a second slower than his teammate, that would mean his real performances with a “fully updated car” would be better than Alonso's.
“For the first time Nelsinho was better than Alonso. He was missing a tenth to Fernando, but he (Piquet) was also missing the modified double diffuser, which only Alonso had. That was worth two tenths,” said the 56-year old Brazilian in an interview with German magazine Auto Motor und Sport.
Despite the encouragements expressed by his father, the fact of the matter is that Piquet is yet to score a point in this year's F1 series, as compared to Alonso's 9 points so far. Renault decided, however, on a change in practice strategy for Piquet starting the Spanish GP, as the Brazilian drove a low-fueled R29 in practice for the first time this season, at Barcelona.
The move was made in order to help the F1 sophomore to get used to a low-fueled car, ahead of the Saturday and Sunday action of each racing weekend.