Tiger Woods, Lindsey Vonn relationship pits Under Armour vs. Nike

Under Armour and Nike's rivalry has reached new heights.

The confirmation on Monday that superstar golfer Tiger Woods and Olympic skier Lindsey Vonn are in a relationship places the two sportsmaker’s head to head against one another on a different stage: Exposure on celebrity gawking websites.

Woods is arguably one of Nike’s biggest — and most valuable — endorsers. While Vonn, a gold medal winner in the 2010 Winter Olympics, has been a a longtime face of Under Armour’s marketing efforts…