The Finn's runner-up position in the Chinese Grand Prix, despite a damaged nose, has left him just three points behind leader Sebastian Vettel in the standings.
Although Lotus is independently owned and cannot match the budgets of rivals Mercedes, Ferrari and Red Bull, Lopez sees no reason why the outfit does not have what it needs to fight them.
When asked by AUTOSPORT if he felt Lotus had the resources and infrastructure to keep up a title push, Lopez said: "We get the same question every year, and every year we have the exact same delta with the other teams.
"We like the position of the underdog, because that is what we are. But in terms of development we have never lagged behind anybody.
"I have always said that maybe we spend our money differently and that makes us an interesting team in the championship.
"We are never going to spend what some others are spending, but that doesn't mean we are not going to compete against them."
Lotus's finances suffered a blow over the winter when talks for a title sponsorship deal with Honeywell collapsed at the 11th hour.
Lopez made it clear that discussions were ongoing with other title sponsors and he was hopeful a partner would be found soon.
"There are a number of title sponsors that we can sign up, but any title sponsor is for three to five years and we think the value we have today in the paddock and the championship is one that should be recognised," he said.
"So you refuse to sign certain things that we could have, because we think we should not undersell ourselves.
"It is a choice, and whenever you make a choice you have to live with the consequences. And the consequence for us is that we [the owners] have to finance more of the team.
"But it doesn't mean the budget has gone down, on the contrary the budget has been increased.
"We have good sponsors, and we are probably not far away from signing something that we are looking for. Then there is no question we will have what we want."
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