ANAHEIM (AP) — Jake Shields won a contentious split decision over Martin Kampmann in his UFC debut Saturday night, extending his career winning streak to 15 fights at UFC 121.

Matt Hamill also won a unanimous decision over Tito Ortiz to keep the former light heavyweight champion winless in the past four years, and Diego Sanchez beat Paulo Thiago by unanimous decision on the undercard of Brock Lesnar’s heavyweight title defense against unbeaten Cain Velasquez at Honda Center.

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Most fans booed when Shields’ hand was raised after a slow, largely uneventful fight with Kampmann. Shields (26-4-1) hasn’t lost an MMA fight since December 2004, going through eight promotions since that defeat.

Shields joined the UFC after defending his Strikeforce middleweight championship in April, and UFC president Dana White has touted the San Francisco-based fighter as a likely challenger for Georges St. Pierre, the league’s nearly unbeatable welterweight champ.

Although Shields wasn’t impressive and appeared to tire in the final two rounds, Denmark’s Kampmann (17-4) didn’t do much to distinguish himself in his second loss in four fights.

Hamill (11-2) controlled his former coach with superior skill on the ground for most of the last two rounds at Honda Center. Ortiz (16-8-1) got off to a strong start, but couldn’t keep up with his younger protege.

Ortiz is 0-4-1 since October 2006, and the crowd in his native Orange County booed him heartily when he walked to the octagon.

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Although he was among the UFC’s top stars for most of the past decade, he thrived mostly as an antihero — and his career eroded during the past four years when injuries, his tumultuous personal life and a rocky relationship with the UFC slowed his career to a halt.

Ortiz looked good in the opening round despite getting a cut on the side of his head, winning on two of the three judges’ cards, but Hamill controlled most of the second round on the ground. Hamill again did most of the damage in the third, and Ortiz raised Hamill’s hand in victory after the final bell.

Sanchez (24-4) controlled the last two rounds in a draining fight against Brazil’s Thiago, even picking up Thiago and carried him across the cage for several steps before dramatically throwing him to the canvas during a particularly acrobatic moment.

Sanchez then pounded away at Thiago (13-3) in the final round to stop a two-fight skid for the former lightweight title contender.

Earlier, former Arena football player Brendan Schaub improved to 7-1 with a unanimous decision over former heavyweight title contender Gabriel Gonzaga, who has lost three of his last four fights.

The UFC returned to the Los Angeles area for the first time in a year with its most anticipated event of the fall. Most of that excitement is centered around Lesnar, the former pro wrestler who missed a full year of fighting with an intestinal illness before returning in July.

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