As soon as the ball hopped past the center fielder, Richard Carthon went into warp speed.

He could have coasted around the bases, but the moment was too big for coolness. He raced around third base about the same time South Florida retrieved the ball from the wall in center field, then slid head-first into home plate to complete a three-run, inside-the-park homer as Tulane went ahead by two runs in the fifth inning.

The Green Wave held on to win 4-3 on Sunday at Turchin Stadium, taking an important series against a fellow NCAA tournament bubble team and climbing into a four-way tie for third place in the American Athletic Conference with one week left in the regular season.

Tulane (31-19, 11-10), ranked No. 45 in the RPI according to WarrenNolan.com, needs to keep winning, but the Wave’s NCAA chances look a heck of a lot better than they did after a 12-0 loss to USF (30-21-1, 11-10) on Friday. The Wave rebounded with two nail-biting, come-from-behind victories.

“It’s all about responding,” Carthon said. “We’ve got heart, we want to win and we’re going to do what we have to do.”

On Saturday, senior third baseman Tyler Wilson said Sunday’s game would be the biggest he had been involved in at Tulane. The tension at Turchin matched his message, with Tulane going up 1-0, falling behind 2-1, retaking the lead on Carthon’s round-tripper and pitching out of tight situations in the last four innings to preserve the win.

USF was 0-for-6 in its last six at-bats with runners in scoring position. The Wave finally exhaled when ace reliever Ian Gibaut struck out two straight batters to end the game with runners on first and second, earning his eighth save and second in as many days.

A defeat would have dropped Tulane to sixth in the AAC, relegating it to long-shot status for a regional bid.

“We really needed to win that game,” Gibaut said. “It was a stressful situation. I got myself into a jam and just had to make the pitches to get out of it.”

Carthon drove in all of Tulane’s runs, some redemption during a rough year at the plate. He entered with a .230 batting average and only 11 RBIs, but his looping single to right field in the third brought home the first run, setting the tone for the day.

He ripped a sinking line drive with runners on second and third in his next at-bat. South Florida center fielder Austin Lueck got caught in between trying to make the catch or field the ball on a bounce, watching helplessly as it rolled all the way to the wall.

It was Carthon’s first career four-RBI game and the first by a Tulane player this season.

“You don’t have too many days like this, even when you are having a great year,” Carthon said. “I’m just going to enjoy this. I’m very thankful we were able to pull out the win.”

Carthon hardly was the only contributor. Senior first baseman Garrett Deschamp, despite an 0-for-10 weekend at the plate, ranged to his right to make two tremendous fielding plays. Jackson Johnson saved a run in the fifth with a diving catch in left field.

Emerson Gibbs (4-2) of Jesuit, who said he did not have command of his curveball, still went six innings. He allowed three runs — the first time he has given up more than one earned run at home all year — but struck out Lueck with the tying run on third base with his last pitch.

Reliever Dan Rankin, boasting a bloated ERA of 6.20, pitched two scoreless innings. He, too, struck out Lueck on his final pitch after hitting a batter and giving up a single with two outs in the eighth.

“He’s made a complete turnaround,” coach David Pierce said. “He was huge for us today.”

First-year South Florida coach Mark Kingston, a Tulane assistant from 2002-08, was ejected in the ninth after Gibaut struck out Levi Borders with a pitch that hit him as he swung through it. The ruling appeared obvious, but with so much on the line, everyone was on edge.

“It’s been a dogfight this entire conference race,” Pierce said. “It’s been tough, at times it’s been fun, it’s been stressful — but it’s the right kind of stress. We’re enjoying it.”