The mixed martial arts show was the UFC's first in Nebraska.
Neer used his strength to force the pace early on but Diaz had the better of exchanges at the fence and took Neer down with a nifty judo throw late in the first round. Diaz also showed some impressive jiu-jitsu, switching positions on the ground.
In the second, the fighters exchanged takedowns with Neer close to latching on a choke. Diaz resisted but Neer had the best of the round. Diaz got the takedown one minute into the third, pressing the action from above in a non-stop round. Diaz briefly had the mount, lost it but kept Neer on his back for much of the round. Two judges scored it 29-28, 29-28 for Diaz while the third had it 29-28 for Neer.
The win was the fifth straight in the UFC for the 23-year-old Diaz. For the 25-year-old Neer, it was a second loss to a Diaz. He was beaten by Nick Diaz, Nate's older brother, at UFC 62 in August 2006. Nick was in his brother's corner Wednesday.
Earlier, a relentless Clay Guida wore down Mac Danzig, winning a unanimous decision to hand the lightweight his first loss in three UFC outings. The judges gave the fight to Guida 30-27, 29-28 and 29-28.
"I just tried to put him on his back and hold him there," Guida said. "And we duked it out on the feet too, man. He's a stud."
Danzig scored with his fists but was taken down twice in the first round. Guida came on strong in the second and was working a choke as the round ended. Danzig responded early in the third with a kimura attempt but Guida controlled him most of the round and finished with a flurry of punches from above.
Diaz won Season 5 of "The Ultimate Fighter" reality TV show while Danzig took Season 6. The Omaha card preceded the TV debut of Season 8.
Alexander hurt Schafer with a knee during a takedown attempt early in the first round, and stuffed several other takedowns. Schafer endured some standup pain, eventually taking his opponent down and working him on the ground. He mounted Alexander (8-4 with one no contest) and punished him from above before locking in an arm triangle at 4:53 of the first round.
Schafer was coming off two straight wins outside the UFC after losing two in a row in the UFC. The jiu-jitsu black belt won his UFC debut by arm triangle, defeating Canadian Rob MacDonald at UFC 62: Liddell vs Sobral.
Middleweight Ed "Short Fuse" Herman lost a split decision to Alan Belcher in a close fight. Herman showed a good chin against the fast hands of Belcher but could not bring the fight down to the ground long enough to take advantage of his superiority there.
Herman ended the close fight in the mount position but it was not enough to deny Belcher the split decision win. Two judges scored it 29-28 for Belcher while the third gave it to Herman 29-28.
"It could have went either way," said Belcher. "That's because me and Ed are very evenly matched."