(CNN) -  

Mitt Romney's internal campaign polling showed President Barack Obama leading Ohio by five points on Sunday, the final day the campaign polled the state, two GOP sources told CNN.

The number represented a sharp final bump for Obama in Ohio, a race that had essentially been a tied race through much of the previous week, according to the campaign's daily tracking.

The polling, which also showed a tight race in Pennsylvania, explains why Romney officials decided to send their candidate on last-minute Election Day visits to Cleveland and Pittsburgh.