Wigan have a poor record against United but have drawn with Chelsea and Liverpool during the last seven days.
“The next game is about as big a test as anyone could get,” Martínez said.
“What you can guarantee from United is that they know when to peak. They know how to be strong at the right moment. December is a month when you see the big players performing so it’s not really a surprise that Wayne is hitting form at just the right time.”
