Mansell, Alain Prost and Ayrton Senna - said the 27-year-old's win was no fluke.
Frank Williams (centre), had to repeatedly rebuff accusations that Pastor Maldonado (bottom right) was at Williams only because of his generous sponsors. Getty/Paul Gilham
"Undoubtedly," Williams said when asked whether Maldonado had the material to one day be a champion as well as a winner.
"I tell you why - because he's very quick and he makes no mistakes."
That has not been entirely true in this most unpredictable of seasons, with five different drivers from five separate teams winning the five races to date, even if the speed has undoubtedly been there.
Maldonado, a very fast but occasionally wild champion in the GP2 feeder series, has at times pushed too hard and crashed when points have been there for the taking but he has also impressed with his pace.
Underrated and dismissed by some as just another 'pay driver', signed up because he brings much-needed sponsorship from Venezuelan state oil company PDVSA, Maldonado showed he is much more than that.
As he said after the race, when asked about the title, "anything is possible".
Before Sunday he would have been laughed at. The pre-qualifying odds of 300-1 on him winning in Spain, reduced from an even more generous 500-1, emphasised that this was a prospect too unbelievable to contemplate.
British bookmakers William Hill said they had received two 10 pound ($16.10) bets at 500-1 and hundreds of smaller wagers.
Williams, however, said his driver's potential "could be very considerable indeed."
"We've got a real racing driver as well. I am just astonished by the way he just controlled himself, didn't make a mistake at all," he declared.
Sunday's victory ended nearly eight years of waiting for the once-dominant former champions, whose last win came with another South American, Colombian Juan Pablo Montoya, in Brazil in 2004.
Last season was Williams's worst in Formula One since the 1970s, with just five points all year, and it was four years since the team that won nine constructors' crowns and seven drivers' titles last appeared on the podium.
They have, however, made a raft of changes and hauled themselves back into mid-table respectability.
Renault, who also power world champions Red Bull and high-flying Lotus, have come in as the engine supplier instead of Cosworth and there have been key changes in the technical department.
"Last year we just weren't up to speed technically," said Williams.
"We had reasonable finance, enough money but things didn't come together properly and we made mistakes.
"With a bit of restructuring... several key people were recruited and they have made a significant difference."
The big question now is whether they can keep up the momentum. While Maldonado was a deserving winner, his achievement also makes winning a realistic aspiration for others who have not yet done so this season.
That list includes McLaren's Lewis Hamilton, Lotus's Kimi Raikkonen, Red Bull's Mark Webber, Mercedes' Michael Schumacher, Ferrari's Felipe Massa.
It also includes Sauber's Mexican Sergio Perez - second in Malaysia in a race he could have won - and like Maldonado representative of a rising generation of initially underrated Latin American talent.
"I truly haven't got a clue," said Williams of his team's chances of winning more this year.
"Everyone who didn't win is seething out there. We're not doing that today but tomorrow morning reality strikes."
Williams board member Toto Wolff sounded a note of caution.
"I can get used to this kind of stuff, I like it," he told autosport.com.
"But I think we cannot expect results like this to happen on every occasion, or that we will be there now as a top contender.
"We have seen Sauber run very competitively in Malaysia, and we have seen (Nico) Rosberg having a tremendous race (winning in China), while here it was us. So it is a tricky situation which the engineers need to understand."