SAN DIEGO -- Ryan Mathews was so nervous before his debut that he had to duck into the bathroom to throw up.
He recovered quickly though. On his second NFL carry, Mathews was pushed back almost to the Chargers' goal line, then powered through linebacker Lance Briggs and ran for 18 yards.
Mathews, the first-round draft pick who will replace the departed LaDainian Tomlinson, gained 50 yards on nine carries and caught two passes for 11 yards. Philip Rivers threw a 28-yard touchdown pass to Legedu Naanee, one of the receivers the Bolts will depend on in Jackson's absence.
"You trust what you see and I've seen him now for three months," coach Norv Turner said. "He's got all the things you need to be an outstanding runner. It's exciting to have him."
The Chargers enjoyed watching Mathews drive through Briggs for the big gain.
"That was impressive," Rivers said. "He showed a little speed there in getting outside."
Said Mathews: "I kind of froze up on the corner or safety or whatever it was. I've got a lot of work to do still. The more I get more games in, the more practices in, the more fluent I'll be getting ready for that stuff."
Mathews said everything was going fast at first. He even beat guard Kris Dielman to the hole a few times.
"He told me to slow down a little bit. That was just the nerves," Mathews said. "I was just trying to get out there fast. That was me just overthinking it."
It was the Chargers' first game since they took a face-plant in a 17-14 playoff loss to the New York Jets, which was Tomlinson's last game with San Diego. He was released in February and signed with the Jets. The Chargers were 13-3 last year, winning their fourth straight AFC West title.
The Bears are coming off a 7-9 finish, their third straight season out of the playoffs.
"We have a lot of work to do, a long ways to go to be the type of football team we're going to be," coach Lovie Smith said. "But it is a start."
"I've liked what Major has done through training camp and tonight also," Smith said. "We need to get him back on the field as soon as possible."
Restricted free agents McNeill, the left tackle, and Jackson, a Pro Bowl wide receiver, are holding out, upset that they haven't been given long-term contracts. The Chargers have threatened to put them on the roster exempt list if they haven't signed their tenders by Friday, meaning they'll be suspended for three games once they sign. They are believed to be willing to sit out the first 10 games, returning for the final six to gain an accrued season.
Rivers played two series and wasn't sacked. Backup Billy Volek was sacked once, midway through the second quarter. Brandyn Dombrowski, the first-string left tackle in McNeill's absence, played two series.
"I thought both our guys who we played at left tackle, against a real good football player earlier, played awfully well," Turner said.
The Chargers had six sacks.
Linebacker Brandon Lang, another undrafted rookie, had a big game. He blocked a punt late in the third quarter that rolled out of the end zone for a safety, and sandwiched Bears second-string quarterback Caleb Hanie along with Antwan Applewhite during a play that resulted in a sack and forced fumble for Applewhite, with Paul Oliver recovering. Hanie hurt his right shoulder on the play.
Bears starter Jay Cutler was in for only one series, going 2 of 2 for 47 yards. He was sacked once.
Hanie threw a 7-yard TD pass to Devin Aromashodu in the second quarter. It came seven plays after San Diego's Ryon Bingham was whistled for a neutral zone infraction as Gould kicked a 52-yard field goal, giving the Bears a first down on the Chargers' 30.
The Chargers committed nine penalties for 66 yards in the first half. Right tackle Jeromey Clary was whistled three times for false starts, including on consecutive plays on the Chargers' second drive.
Chargers WR/PR Craig Davis sustained a hip pointer on a punt return in the first quarter and didn't return. ... Chicago LB Hunter Hillenmeyer sustained a foot injury.