Ferrari all fired up despite Merc's start
"I don't think it is as bad as the championship looks," Leclerc said. "We have had opportunities: once I did a mistake; on the other one we had an issue that cost us a better result. I think overall the performance is there - we just need to try to put everything together, in most of the occasions, to be using our full potential."
Ferrari come back to the Circuit de Catalunya knowing they are 74 points adrift of their rivals and in real need of stopping them reeling off a record fifth consecutive one-two in today's race.
"I don't think Mercedes were that far behind us in the testing here in Barcelona. It was only on the final day that they pushed and then did lap time," added Leclerc.
Meanwhile, Vettel said he was shocked to learn that the atmospheric Interlagos circuit in Sao Paulo is to be axed as the home of the Brazilian Grand Prix.
The three-time winner of the race in the rolling suburbs of the sprawling city said he felt like a fan losing an important part of the sport's history when he heard the news.
Brazil President Jair Bolsonaro said earlier this week that the race was to move from Sao Paulo to Rio de Janeiro next year.
"I wasn't aware that it was going to happen," he said. "I heard some rumours, but I think it's a shock. Interlagos is a great place, a lot of history. The old track at Interlagos is even better than the current one!
"I cannot think of anything, other than maybe the track being a little bit short, that Interlagos is missing... It's a real shame. I'm sort of a fan of hanging on to old things..."
Apart from the history of Interlagos, Sao Paulo has also given Formula One several great drivers including Ayrton Senna, Rubens Barrichello and Felipe Massa.
The defending five-time champion is a single point behind his Mercedes teammate Valtteri Bottas in the embryonic standings.
Vettel is confident that Ferrari are in good shape and ready for the challenge: "The car was really good in testing," he said. "Then we arrived in Australia and struggled to feel the same and the first four races have been up and down. Deep down, we know the car is strong. And the spirit is as good or better than last year.
"We're in good shape and we're confident about the parts we bring here," he said, referring to a new upgraded power unit and other upgrades to be introduced this weekend.
"This weekend will be interesting for us because we had a good feeling here not so long ago - so it will be interesting to see how it behaves this weekend.
"I'm confident if we can get to the level, we will be very competitive."
Teammate Charles Leclerc also insisted that the picture is not as bleak as it may appear. The Monegasque racer, whose huge potential has yet to be rewarded with a maiden victory in Formula One, said he did not think Mercedes' dominance was a true reflection of their respective team performances.
Sebastian Vettel insisted that Ferrari's team spirit remained strong despite rival Mercedes reeling off an unprecedented four straight season-opening one-twos.
The four-time champion German admitted that the Italian outfit had struggled in the opening races after looking so strong in pre-season testing at the Circuit de Catalunya.
But he said he expected to see the car and team bounce back to their best on returning to the track for today's Spanish Grand Prix.
However, it's a huge task facing Ferrari as Lewis Hamilton will seek to complete a hat-trick of Catalan triumphs and regain the lead in this year's drivers' world championship.