Republican presidential candidate, former US Sen Rick Santorum, talks with voters at a polling station in Chapin, South Carolina, on Jan. 21, 2012. [Photo/Xinhua]

WASHINGTON - US Republican presidential hopeful Rick Santorum Saturday was projected by major TV networks to win the Louisiana primary.

The win would give the Pennsylvania senator a much needed victory after a bad week.

After the polls closed in the southern state, major TV networks including CNN, FOX and NBC all projected Santorum will win the state, based on exit poll numbers.

The state has a close primary, meaning only registered Republicans can vote, and Santorum, a social conservative, was heavily favored to win.

His win came after frontrunner Mitt Romney's 12-point victory in Illinois Tuesday, giving him breathing space as Romney solidifies lead in delegate count.