Eric Boullier says McLaren did not take any shortcuts with the chassis design of the MCL33 despite the challenge of incorporating the new Renault engine.
McLaren decided to ditch Honda after three frustrating seasons, but the final call to switch to Renault power for 2018 came very late in the design process.
Technical director Tim Goss said the different packaging of the turbo and energy recovery systems required to major work to accommodate it and racing director Boullier heralded the approach taken by his team to deal with the challenge.
"The design, engineering and aerodynamic departments have done an incredible job delivering a new car with a new power unit in an extremely short timeframe," he said at the launch of McLaren's 2018 challenger on Friday.
"We never took the easy route or looked to shortcut a process or a solution; and the result is a car that is neat and well-resolved.
"That said, we are under no illusions that it will be difficult to splinter the hegemony at the front; and that the midfield will be full of well-funded, experienced outfits with plenty to prove.
"We are humble about the challenge ahead, but feel we've prepared well, have a solid package that we can build upon and exploit as the season progresses, and have two excellent drivers who will make the difference in races."
Goss said changing power units was "a big deal" because the differences between the Honda and Renault concepts were so dramatic.
"There are two families of engine out there; the Mercedes and Honda concept, with the compressor at the front of the engine, turbine at the back, MGU-H sat in the vee; and the Ferrari and Renault approach, where the turbo-charger is at the back of the engine, and the MGU-H sits forwards into the vee," said Goss.
"The advantage of the Renault layout means that we can push the engine forwards, but then you have the compressor at the back of the engine, so you've got to get the outlet pipes forward without impacting the packaging.
"We had to redesign the back of the chassis, the gearbox bell-housing area, the rear suspension, and the cooling layout.
"That was two weeks of intense effort to get right.
"But it was something we were somewhat prepared for, because we knew it might happen, and it's amazing what people can do in such a short space of time when the chips are down and you've got a really clear mission."
Goss added the orange and blue-liveried MCL33 looks "evolutionary" but the team will continue "enhancing" the car through testing and across the season.