Whitmarsh was contemplating life without Lewis Hamilton on Friday after the 2008 world champion opted to jump ship and join Mercedes.
As replacement, the Woking-based marque have appointed only their second Latin American driver since Ayrton Senna last drove for the team in 1993.
Mexico's Sergio Perez has been heavily supported throughout his driving career by telecommunications giant Telmex, run by one of the world's richest men in Carlos Slim.
Sauber have benefited from the support of a number of Mexican sponsors over the last two years since the 22-year-old joined the Swiss-based team, and it is certain McLaren will now do likewise.
Although losing Hamilton is a bitter blow to Whitmarsh, his belief in Perez having the talent to become a champion is obvious, and he also has other - commercial - advantages.
"Lewis and Jenson are great ambassadors and great assets, but for some of our partners to have a European and a Latin in our team is very appealing," said Whitmarsh.
"You'll never please everyone, but there were some partners who were uncomfortable with the Britishness of our team and its line-up, and clearly we have a broader appeal now."
Those commercial considerations were perhaps why Perez was given the opportunity rather than Paul Di Resta, despite the Scot's impressive performances over the last two years at Force India.
"I know Paul very well and I rate him," added Whitmarsh. "But it would probably have been a little bit too continuing with the British theme to have gone that route."
Whitmarsh has confirmed discussing Perez's appointment on Thursday with Slim, and it is McLaren rather than the telecomms billionaire who will be paying their new driver's salary.
But Whitmarsh is aware of the potential lucrative repercussions of bringing in Perez as he said: "I did have a conversation with Carlos. But we have made an offer to Sergio, we are paying him well and there are no side deals or other deals on it.
"I'm not saying that ultimately there may be other fresh partners coming forward because of it, but that wasn't the motivating force.
"We've a tremendously strong partner line-up of investors. That's solid and we are confident and comfortable with that."
With McLaren's primary sponsor being Vodafone and given Perez's connections to Telmex and Slim, there would appear to be a conflict of interest.
However, Vodafone and Telmex are known to be forging links in the South American market, and Whitmarsh does not foresee any future issues.
"I have to say they have been very supportive (Telmex and Slim)," said Whitmarsh.
"They understand we have a partnership with Vodafone and they are respectful of that."