Mitt Romney has closed to within striking distance of Rick Santorum in Santorum’s home state of Pennsylvania, according to a new poll from Quinnipiac University.

The poll shows Santorum leading Romney 41 percent to 35 percent in the Keystone State, which is shaping up as the main battleground of the April 24 primaries— the next set of contests after today’s primaries in Wisconsin, Maryland and the District of Columbia.

The poll is the second to show Romney closing in on Santorum in Pennsylvania. Last week, a poll from Franklin and Marshall College showed the two candidates in a statistical tie.

That poll prompted Santorum to dismiss the pollster as a “Democratic hack.” But the new Quinnipiac poll seems to back up the idea that Santorum is losing ground in his home state. Quinnipiac last month showed Santorum leading in Pennsylvania by 14 points.

This month’s poll shows Santorum with only a slightly better favorable rating in the state than Romney.

Fifty-seven percent of Pennsylvanians say their former senator should stay in the presidential race, while 33 percent say he should drop out.

Santorum acknowledged recently that his home state is a must-win for him. Without it, and assuming he loses in Wisconsin today, he would likely lose every state to hold a contest in April.