Tesla Inc.'s rapid rise to become the world's most valuable carmaker could mark the start of a new era for the global auto industry, defined by a Silicon Valley approach to software that is overtaking old-school manufacturing know-how.

Tesla's ascent took many investors by surprise. But executives at Daimler AG, the parent company of Mercedes-Benz, had a close-up view starting in 2009 of how Tesla and its chief executive, Elon Musk, were taking a new approach to building vehicles that challenged the established system.

Daimler, which bears the name of the man who invented the modern car 134 years ago, bought a nearly 10 percent Tesla stake in May 2009 in a deal which provided a $50 million lifeline for the struggling start-up.