The Briton revealed that he made mistakes on his two quick laps aboard the #51 Ferrari 499P Le Mans Hypercar in the opening 15-minute qualifying session.
That left him outside the top 10 cars that progressed to the final session in which team-mate Antonio Fuoco claimed pole position by half a second in the sister Ferrari.
“I screwed up both laps basically,” Calado told Motorsport.com. “I went long into Turn 5 [Les Combes] on the first lap; I lost the car, my mistake.
“Then on the second lap I was two or three tenths up and then at Turn 12 [Fagnes], I did exactly the same thing — so I messed up twice.”
Calado’s best time of 2m03.002s put him 11th in the times, which meant he missed out on progressing to Hyperpole by just two hundredths.
“It was tight: the reality was that without those mess-ups I could have been in Hyperpole,” said Calado, last year’s Le Mans 24 Hours winner last year with Alessandro Pier Guidi and Antonio Giovinazzi.
The Briton conceded that he would not have been able to fight with Fuoco for the top spot had he made it into Hyperpole.
“I couldn’t have challenged Antonio - he was just too fast,” he said. “It is difficult because that was only my third ever qualifying in this car.
“It’s quite a big step to adapt from a car set up for the race, which is what I am used to. Fuji last year was my last qualifying, whereas Antonio does all the quali sessions in the other car, which I think is good idea.”
Calado insisted that he still has confidence going into Saturday’s Spa 6 Hours based on the performance of the #51 Ferrari through free practice.
“Our performance on paper from our race runs looks pretty good,” he explained.
“We are confident we have got a plan for the race.
“Unlike last time at Imola, here you can overtake and there is a lot more tyre management involved, so I hope we can fight forward.
“I’ve just to try to get this quali thing out of my head and then focus on the race.”
