Danish youngster Kevin Magnussen, whose father Jan raced in Formula One during the 1990s, put McLaren on top of the timesheets on the first day of a young driver test in Abu Dhabi.
The 20-year-old was a genuinely young driver in a session that also included the 31-year-old pair of Nicolas Prost, son of French former champion Alain, with Lotus and McLaren reserve Gary Paffett.
Speaking to reporters at last weekend's Abu Dhabi Grand Prix, McLaren team principal made no apologies for using the test more for development of the existing race car than to introduce fresh faces to F1.
"With the limitation on track testing, all teams play a different game," he explained. "A lot of the small teams use young driver testing for revenue and a team like ours uses it largely for a range of technical developments.
"I'd be disappointed if we come out of that (test) without arriving (at the next race) in Texas with something we can put on the car or some better understanding that makes us quicker," added the Briton.
There are two races remaining this season, the US Grand Prix in Austin and Brazil, and McLaren are battling Ferrari for second place in the constructors' championship.
Paffet and fellow-Briton Oliver Turvey, 25, will do the bulk of McLaren's testing over the next two days at the Yas Marina Grand Prix circuit.
Champions Red Bull had promising Portuguese Antonio Felix Da Costa, who was second fastest, in their car while Sauber tried out Dutchman Robin Frijns.
Caterham also ran Dutch driver Giedo Van der Garde.