Rick Santorum, hoping to narrow the Republican presidential contest to a two-man duel with Mitt Romney, yesterday put pressure on Newt Gingrich in his old home state of Georgia, suggesting that a loss here on Super Tuesday could force the former speaker out of the race. “There are good people in this race, people I admire,’’ Santorum said in a veiled reference to Gingrich. “But this race is narrowing down, and we need the people of Georgia to stand with the conservative, to make sure the Washington establishment doesn’t again give us another moderate Republican who will not motivate our country and will lose this election in the general election.’’ Gingrich, whose once high-flying campaign has been reduced to a battle for Georgia, bluntly acknowledged that he must prevail in the state he represented in Congress for 20 years.