For the second time in two seasons, the No. 23-ranked Tigers rallied in the late innings to deny Pettis, who has 40 career saves, the satisfaction of nailing down a monumental postseason win.
LSU posted a two-out rally to tie the score in the bottom of the ninth against Pettis, who was six for six in save situations in the regular season and has been called a "Hall of Fame competitor" by UCI Coach Mike Gillespie.
Another two-out rally off Pettis in the 11th allowed the defending national champions to turn a 10-9 deficit into an 11-10 win in the first round of the NCAA Los Angeles Regional Friday at UCLA's Jackie Robinson Stadium.
The loss puts No. 21-ranked UCI (37-20) into an elimination game today at 2 p.m. against Kent State (39-24).
A bases-loaded double by pinch-hitter Trey Watkins just over the glove of retreating Sean Madigan near the right-field warning track, sent Pettis and the Anteaters walking off in disgust and, perhaps, disbelief Friday.
Watkins' blow was the last of a series of punches and counterpunches in a game that lasted four hours, three minutes and included 19 players for each team, 35 combined hits by 20 different players, 356 pitches and enough emotion to last an entire postseason.
"I really don't know how to describe it," LSU Coach Paul Mainieri said. "You don't see games like that very often."
Gillespie, who has guided 18 teams in regionals during 23 seasons as a Division I coach, was similarly overwhelmed.
"I'm sort of having a hard time remembering what all happened," said Gillespie, who called the loss difficult. "So much happened. It was a battle and I think everybody left it on the field. I'm extremely proud of how hard we played. We ask our guys to play every pitch and they did."
Every pitch had meaning in a game that had five lead changes.
Senior catcher Francis Larson hit two home runs and collected his fourth run batted in by delivering a squeeze bunt that gave UCI its final lead in the top of the 11th. Larson extended his school-record total to 24 career home runs.
The importance of Larson's second sacrifice bunt of the season, which traveled about 45 feet, might have eclipsed his two dingers that carried nearly a combined 800 feet over the left-field fence, because it put UCI on the verge of victory yet again.
UCI led, 9-8, after scoring twice in the ninth, with an RBI double by sophomore pinch-hitter Jordan Leyland, then an RBI single by junior left fielder Ryan Fisher quieting the substantial, and vocal, LSU crowd.
"I thought we were going to be able to close it out," Larson said. "Pettis is a gamer. I thought he was going to come in there and shut the door. It just didn't go our way."
LSU kept the door open when Blake Dean punched a two-out single through a hole created when Gillespie deployed third baseman Brian Hernandez as a fourth outfielder against the left-handed-hitting Dean.
A pinch-runner for Dean scored when Austin Nola's single bounced in front of a diving attempt by Madigan and the relay throw to Larson skipped in the dirt as Johnny Dishon slid home.
After a scoreless 10th, UCI senior first baseman Jeff Cusick walked to open the 11th. He went to second on a Jordan Fox sacrifice bunt and stopped at third on a pinch single by Ronnie Shaeffer to set up the Larson squeeze.
Pettis, a three-time first-team All-Big West Conference hurler who expanded his closer roll to join the weekend rotation this season, retired the first two he faced in the 11th.
But Austin Nola walked and Alex Edward reached on an infield single to deep short.
Watkins, who lost his starting job in left field after being slowed by a dislocated elbow, drove a 1-2 pitch off the fence in right to spark a wild LSU celebration.
It has become an all-too-familiar scene for UCI and its fans.
Trailing, 7-4, in the ninth inning of a 2008 Super Regional Game 2 in which UCI was three outs away from its second straight trip to the College World Series, LSU posted five runs against Pettis to claim a 9-7 triumph. The Tigers won the next day, 21-7, to advance to Omaha.
"I think we are a tough team," Larson said about the possible affects of the gut-wrenching setback. "I think we were a tough team when we lost in '08 against LSU and I think we're tough now. I think we'll spring back. And I think our guys will pull together."
Senior All-American Danny Bibona, who came in with a conference-best 2.10 earned-run average, gave up seven runs in his first start in four weeks after being sidelined by sore rib muscles. The seven runs were the most allowed by the two-time Big West Pitcher of the Year the last two seasons. Two of those runs were unearned, courtesy of a Bibona throwing error.
Evan Brock and Nick Hoover pitched well in relief for UCI, to allow the 'Eaters to rally.
"Irvine played us as hard as we expected them to play us," Mainieri said. "They are just an impossible team to hold down. They sock the ball all over the field and they are almost impossible to strike out.
"We got a big lead there and did a tremendous job against Bibona. I'm not sure that he has had many games like that in his career. We thought we were in pretty good shape there and thought we had a good lead. [The 'Eaters] just kept chipping away, chipping away, got back in the game, tied it and took a lead."
Fisher went three for five with two RBIs and a home run, while Madigan, senior Casey Stevenson, Cusick and junior Drew Hillman also had two hits apiece for UCI.
Junior catcher Micah Gibbs had a three-run home run off Bibona in the fifth and finished with five RBIs.
Los Angeles Regional
LSU 11, UC Irvine 10
SCORE BY INNINGS
UCI 0 2 0 0 1 0 2 2 2 0 1 — 10 18 1 LSU
0 0 2 1 4 0 1 0 1 0 2 — 11 17 1 Bibona, Brock (5), Hoover (7), Pettis (9) and Larson; Ross, Bertuccini (7), Cotton (8), LaSuzzo (8), Bourgeois (9), Rittiner (9), Alsup (10) and Gibbs. W – Alsup, 5-0. L – Pettis, 9-4. 2B – Madigan (UCI), Stevenson (UCI), Leyland (UCI), Watkins (LSU), Katz (LSU). HR – Larson (UCI) 2, Fisher (UCI), Gibbs (LSU), Edward (LSU).