LIVONIA, Michigan (AP) — Mitt Romney scored a hard-fought triumph in his native state of Michigan and powered to victory in Arizona on Tuesday night, dealing a blow to chief rival Rick Santorum and gaining precious momentum in the turbulent Republican presidential race.

Romney’s victories cement his status as his party’s front-runner to challege President Barack Obama in the November election, and injects his campaign with new energy 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.

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Romney is viewed as the candidate best positioned to beat Obama, and he has the backing of much of the Republican establishment. But Santorum has captured the heart of the party’s conservative base, which has no doubt about the authenticity of his views on social issues such as abortion and considers Romney too moderate.

“We didn’t win by a lot but we won by enough, and that’s all that counts,” Romney told cheering supporters on Tuesday night.

With 71 percent of Michigan’s precincts reporting, Romney had 41 percent to Santorum’s 37 percent. Texas Rep. Ron Paul was in third place with 12 percent, and former House Speaker Newt Gingrich was bringing up the rear with 7 percent.

In Arizona with 43 percent of precincts reporting, Romney was leading with 49 percent to Santorum’s 25 percent. Gingrich was third with 16 percent and Paul came in last with 9 percent.

Copyright 2012 The Associated Press.