LIVONIA, Michigan - Mitt Romney has won the Republican primary race in his native state of Michigan, dealing a blow to his chief rival Rick Santorum and cementing his status as his party's favored candidate to run against President Barack Obama.

US Republican presidential candidate and former Massachusetts Governor Mitt Romney waves with his wife Ann (2nd L) and son Tag (L in Novi, Michigan, February 28, 2012. [Photo/Agencies]

Earlier, Romney easily won the second primary held Tuesday, in Arizona. He had been the heavy favorite and his opponents had spent little time campaigning there.

Romney's sweep of both contests injects his campaign with new momentum ahead of next week's crucial contests in 10 states, known as Super Tuesday. Santorum had needed a win or a very close second to show that he was still in play and that victories earlier this month in Minnesota, Colorado and Missouri were not a fluke.