Murray had a chance to hit back immediately when a mis-hit Federer forehand gave him a breakpoint, but his opponent saved that before holding to establish a 5-2 advantage.
The Chinese showed signs of recovery by holding his next two service games, and even found himself with a breakpoint in game eight as Murray's concentration wavered.
Louis during a campaign swing through one of 16 states holding primaries or caucuses March 7 -- a night the candidate has targeted as a make or breakpoint in his campaign.