ARLINGTON, Texas — The December trends hold: Philip Rivers and the San Diego Chargers are perfect, while Tony Romo and the Dallas Cowboys are perfectly miserable in the most important month of the regular season.

Rivers broke a fourth-quarter tie with a 14-yard touchdown pass to Antonio Gates, then followed with a drive that ate up more than 7 minutes and ended in a field goal, giving San Diego a 20-17 victory yesterday.

San Diego (10-3) won its eighth straight and is on the verge of clinching the AFC West. The Chargers are 16-0 in December since Rivers became their starting quarterback.

"You don't want to fade out in December, you want to be peaking," Rivers said. "We've been able to do that the past few years. We just hadn't sustained it into January. Hopefully this will be the year we keep this thing going into 2010."

San Diego's last 11 December wins have come under Norv Turner, whom Cowboys owner Jerry Jones decided not to hire last time his head coaching job was available. Jones picked Wade Phillips instead and hasn't gotten his money's worth in December: 3-8 after this loss; he's lost a total of seven games over three Septembers, Octobers and Novembers.

The Cowboys (8-5) are stuck with consecutive losses for the first time this season, and are headed to New Orleans to face the undefeated Saints on Saturday night.

The Chargers iced the victory by using up 7:17 on a 15-play drive that ended with a 34-yard field goal by Nate Kaeding, which made it 20-10 with 1:56 left.

SAN DIEGO 7 3 0 10—20

DALLAS 3 0 7 7—17

First Quarter

Dal—FG Folk 31, 8:36.

SD—Tomlinson 1 run (Kaeding kick), 4:30.

Second Quarter

SD—FG Kaeding 29, 10:18.

Third Quarter

Dal—Austin 6 pass from Romo (Folk kick), :00.

Fourth Quarter

SD—Gates 14 pass from Rivers (Kaeding kick), 10:56.

SD—FG Kaeding 34, 1:56.

Dal—Crayton 9 pass from Romo (Folk kick), :02.

A—90,552.

SD Dal

First downs 21 22

Total Net Yards 341 347

Rushes-yards 31-73 27-108

Passing 268 239

Punt Returns 2-18 0-0

Kickoff Returns 2-42 4-93

Interceptions Ret. 0-0 1-0

Comp-Att-Int 21-32-1 19-30-0

Sacked-Yards Lost 1-4 1-10

Punts 3-42.0 3-56.3

Fumbles-Lost 0-0 1-0

Penalties-Yards 5-24 6-68

Time of Possession 30:05 29:55

RUSHING—San Diego, Tomlinson 21-50, Sproles 7-22, Rivers 3-1. Dallas, Jones 10-51, Barber 14-47, Choice 2-11, Romo 1-(minus 1).

PASSING—San Diego, Rivers 21-32-1-272. Dallas, Romo 19-30-0-249.

RECEIVING—San Diego, Jackson 7-120, Gates 4-44, Floyd 3-40, Tolbert 3-19, Wilson 1-21, Naanee 1-16, Tomlinson 1-9, Sproles 1-3. Dallas, Austin 6-71, R.Williams 4-74, Witten 4-49, Crayton 2-31, Barber 2-22, Jones 1-2.

MISSED FIELD GOALS—Dallas, Folk 42 (WL).