"We haven't given him a great car so far," Whitmarsh admitted. "As a team have got to step up and support the young driver who has got an enormous amount of talent.
“He's still a very young guy in a big team with lots of expectations so you're under a lot more scrutiny and it's tougher," Whitmarsh added. "Sergio is not satisfied with his performance last weekend - he's a young driver and it was a difficult weekend."
Perez himself confirmed Whitmarsh's words. "I am very disappointed but it was a very difficult race. It was the worst weekend for us in terms of pace," he sighed. "I have a lot to learn from this weekend and a lot to analyse."
Perez did receive some public support from his senior team mate Jenson Button, however, who said that "A guy who races for a top team like McLaren has more pressure on his shoulders.
"When you're in the middle of the pack, it's tough. You can make one move, one lock-up, and it costs you three places," added Button. "It's not an easy position to be in. You've got to make the best of it, and experience does help in that situation."
Button's experience has certainly shown by comparison, which has only added to the pressure on the underperforming junior driver: "He's up against Jenson, who has done a fantastic job with the car," agreed Whitmarsh after Button succeeded in delivering a fifth place finish for the team in China despite the below-par form of the MP4-28 so far this season.
Outside the team, McLaren's decision to appoint Perez in haste after longtime driver Hamilton announced his defection to Mercedes in mid-2012 was under fire from some big names in the sport, including Sky Sports F1
commentator and former F1 driver Martin Brundle who felt that McLaren missed a trick not signing Nico Hülkenberg instead.
"I would have signed him ten times before Perez," Brundle told Speed Week
after being impressed by the German driver's two back-to-back points finishes for Sauber, which ironically is Perez' old team. "I still don't understand why McLaren didn't sign this guy," Brundle added. "His talent is abundantly clear" - implicitly implying that this is not the case with Perez.
Asked in China on Friday if he felt his move to McLaren had been a mistake, Perez insisted that it wasn't and that he was still determined to prove himself and that he was desperate for his first success with the team and for his maiden F1 victory after coming close with two runner-up finishes in 2012 in Malaysia and Italy.
But for all the brave face he can muster, it's certainly a very different story from that of Lewis Hamilton who has described his own move to Mercedes this season as "a dream start" and "just the most satisfying experience - I couldn't be happier with my decision."
Unfortunately, Perez can't say the same so far about his tenure in Woking.