Although the Woking-based team has made some progress in understanding where it has gone wrong with the design of the MP4-28, Perez says he is under no illusion about how much more the team needs to do to get itself back to the front.
When asked in an interview about whether he thinks the current McLaren can become a winning car, Perez said: "I think we are very far from that. We have to do big updates, big improvements.
"At the moment we are one second per lap slower [than the pace setters] - so we are not in the position that we want. You don't win races by being one second off the pace."
Despite his downbeat assessment of McLaren's short-term plight, Perez thinks it essential that the outfit still keep pushing on to try and improve its current car.
But he also makes it clear that McLaren must not compromise its efforts for next year's challenger because it cannot afford another lacklustre campaign.
"We have to give our best for a couple of months because at some point we have to fully focus on 2014," he explained. "There is no chance we can waste another year.
"We want to win, we are a winning team. The priority is to maximise this year, try and get the best possible result and then look forward to the future."
While Perez is aware of the problems McLaren faces, he thinks on a personal front that he has made huge strides in his own performance behind the wheel.
"I would definitely have liked to be in a much better position than I am now; coming here and fighting for race wins rather than trying so many times, but this is life and this is F1. There are no guarantees at all.
"I think I am happy because I have learned a lot. I have grown up a lot as a racing driver, so in that respect I can be happy.
"I am a much better driver than I was at this stage last year even though I had maybe double the points. I am in a better position as a driver, so I am happy."
He added: "Being at McLaren makes me a more complete driver: to know exactly what is going on with the tyres, with the race.
"Last year I was pretty good at managing the tyres, so I thought I was very good.
"When I came to McLaren with a very different car, a very different way to drive, I found myself against Jenson [Button] that I was not so good, so I had to learn and work on that.
"And I think right now I am driving very different to how I was driving in Sauber, and still I can be good in managing the tyres. Those things are important right now in the sport."
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