Speaking to reporters at the Monaco Grand Prix, social highlight of the calendar and sixth race of the year, the Malaysian described 2012 as "a blip, a disappointment' for a team still seeking their first point in more than three seasons.
"I thought by this year we would definitely be in the midfield," he said after a presentation for a memorandum of understanding between his Tune Group and Abu Dhabi-based brokerage ADS Securities.
"I think we tried when (aerodynamics head) John Iley came over (from McLaren) to try to be a bit too clever last year with the blown diffuser and that screwed us up.
"If we had just continued on the normal pattern we probably would have been in the midfield by now. We've learned the hard way," added Fernandes, whose team have finished 10th for three years in a row but were almost beaten by 11th placed Marussia last season.
Caterham, who started out in 2010 as Lotus Racing and then became Team Lotus for their second season, rang the changes at the end of 2012 by replacing experienced drivers Vitaly Petrov of Russia and Finland's Heikki Kovalainen.
In their place, they hired inexperienced Frenchman Charles Pic and Dutch rookie Giedo van der Garde, who both brought sponsors with them.
Fernandes said the initial thinking had been to write off 2013 to prepare for the far-reaching engine changes being introduced in 2014 but that approach had changed since last month's Bahrain Grand Prix when their updated car looked more competitive.
"I said 'let's put everything into 2014', but we suddenly saw the wind tunnel working," he explained.
"Up to Bahrain we just had the old car but we made some modifications for Bahrain and we got much closer to the midfield and we were much faster than Marussia. We got more downforce - we haven't captured all of it yet - but we know that the wind tunnel is working."
Fernandes, who has appointed Frenchman Cyril Abiteboul as principal of the team and has made only rare appearances at races this season, said he had gone into Formula One with his eyes open.
The chairman of former Premier League club Queens Park Rangers said there was no question of his enthusiasm for the sport waning and emphasised he was in for the long term despite the lack of success on the track.
"On the business side, it's done everything I wanted it to," he said.
"It's not about winning the world championship per se, it's about building a car, which has always been my dream and that's progressing quite well.
"I don't need to be world champion to sell lots of cars. I need to have a brand where people say 'I know that brand' and have a price point where everyone around this table could aspire to own one," he added.
Caterham, who last year signed a deal with Renault to revive the Alpine brand, will use the French manufacturer's engines again next season.
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