The day after winning the GOP Senate nomination in Illinois, Rep. Mark Kirk’s campaign released a poll Wednesday that showed him ahead of state Treasurer Alexi Giannoulias (D) by 12 points.

The poll was taken in the hours before Tuesday’s primary, on Monday and Tuesday, and the results showed Kirk led Giannoulias 47 percent to 35 percent. The Magellan Data and Mapping Strategies poll surveyed 885 Illinois voters and had a margin of error of 3.3 points.

Other surveys in the past few months have shown the Senate race to be a statistical tossup. Giannoulias won Tuesday’s bruising primary by less than 5 points, and with the hits he took late in the primary it’s understandable that his numbers have fallen. Kirk, meanwhile, escaped relatively unscathed from his primary because none of his opponents waged an effective challenge.

The campaign also released numbers that showed the Congressman with a better standing among voters. Kirk had a favorable/unfavorable margin of 5 points, while Giannoulias had a favorable/unfavorable margin of negative 15 points.