Visitors to Newt Gingrich’s presidential campaign website Tuesday afternoon were greeted with a new slogan: “Last conservative standing.”

While most observers took Rick Santorum’s departure from the race as a sign that Mitt Romney had finally claimed the title of Republican nominee, Gingrich crowed that he finally had his one-on-one shot at the front-runner.

“There’s still a lot of running room,” the former U.S. House speaker from Georgia said in a radio interview with conservative commentator Sean Hannity. “There’s no question Romney’s the front-runner, but he has not locked this up. And most people expect somebody who’s willing to stand up for the whole game and not just the first half.”

Santorum, a former U.S. senator from Pennsylvania, similarly had said the race was at the halfway mark just last week.

But at an appearance in Gettysburg, Pa., he said a weekend spent in the hospital with his young daughter, Bella, who has a rare life-threatening genetic disorder, caused him to reassess his candidacy. Santorum did not explicitly endorse any of the remaining candidates but vowed to stay involved in the effort to defeat President Barack Obama in the fall.

Gingrich has repeatedly scaled back his strategy, and of late had been talking mostly about crafting a conservative platform for the GOP convention in order to force Romney as far to the right as possible. But the Santorum news seemed to give Gingrich new life Tuesday.

He talked anew of chances to win delegates in Delaware, Pennsylvania and New York, which are among the next primary contests April 24. Those votes will provide a sense of whether Gingrich can combine his support with Santorum’s into a conservative bloc -- a scenario not supported by polls in previous states.

In May the race moves to Southern contests that could be more favorable for Gingrich, including May 8 in North Carolina.

Gingrich, ever fond of sports metaphors to describe his struggling candidacy, noted on Hannity’s show that neither golfer in Sunday’s Masters playoff -- Bubba Watson and Louis Oosthuizen -- began the day in first place. He insisted that despite the obvious signs that a Romney-Obama general election is under way, the GOP primary fight continues.

“It’s a one-step-at-a-time process to see how that all unfolds,” Gingrich said of his comeback hopes. Now that it's "down to two choices of a conservative and a moderate," he said, it will be interesting to see "how it all plays out in places like North Carolina.”