Former House speaker Newt Gingrich, campaigning Monday in Nashua, N.H., called New Hampshire a “wide open” race, at least for third place, and said he heads into Tuesday’s GOP presidential primary with “optimism and lots of energy.”

Gingrich talked to reporters after an appearance at BAE Systems, a defense contractor, in Nashua. He predicted that Mitt Romney would win the primary but said he believes the former Massachusetts governor is “sliding fast.”

Rep. Ron Paul (Tex.) will finish second, he said, unless his position on Iran “has really hurt him.”

Gingrich sees himself in a hard-fought contest for third with former senator Rick Santorum (Pa.) and former Utah governor Jon Huntsman Jr. If all three are closely bunched, he said, New Hampshire will matter little.

“I think what matters next is late tomorrow night getting to South Carolina,” he told reporters. “I think it really is a showdown.” South Carolina holds its primary Jan. 21.

Gingrich said the key for him after New Hampshire is making a connection with southern voters.

“I just have to prove as a Georgia conservative that I have an affinity for South Carolinians,” he said. “I think I’ll do well.”