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ENGLEWOOD, Colo. --** Before the Broncos and Chargers met in Week 15, Denver had the league's best third-down offense. By the end of the season, San Diego did, and the divergent performances in the Chargers' 27-20 win Dec. 12 had much to do with the Broncos dropping to No. 2 in the league.
That game -- the first of three without wide receiver Wes Welker, sidelined because of a second concussion in four games -- saw the Broncos go 2-of-9 on third downs, their worst ratio of the season to that point. Ten days later, when Welker missed his second consecutive game, they struggled even more, going 2-of-11.
They stopped the bleeding in Oakland in Week 17, but by the time the fourth quarter of the season ended, the Broncos had converted just 18 of 48 third downs in Weeks 14-17, and only once finished a game above 40 percent. During that span, Welker was limited to one half of football. Clearly, he was missed.
"Big time," said wide receiver Eric Decker. "He's a guy that has done very well on third down -- and just any down it is. When you lose a weapon like that you have to fill the shoes and I don't think we as a team did a good enough job of having a successful first down, minimizing the third and longs and taking advantage of some of the opportunities we had."
Prior to Welker's second concussion, the Broncos converted 48.2 percent of their third downs. Their percentage was just 39.0 in the three-and-a-half games they played without him.
Meanwhile, the Chargers converted 31 of 55 third downs and never converted less than 50 percent in a game. That helped the Chargers finish with the second-highest third-down success ratio of any team in the last four years, and as the league leaders in time of possession, averaging 32 minutes, 59 seconds per game.
"That's why you have all the sustained drives," said Chargers head coach Mike McCoy. "That's critical in any game, to win the time of possession, and to nurture downs."
The Chargers have held a time-of-possession advantage in 14 of 17 games this season. They are 10-4 when they have an edge in that statistic, and 0-3 when they don't.
But the Chargers deviated from their third-down trend Sunday in Cincinnati, going 4-of-12 on third downs, a season-low 33.3 percent. That dropped them to 3-6 when they convert less than 50 percent of their third-down opportunities, compared to 7-1 when they do.
The Bengals also prevented the Chargers from flourishing on third downs in spite of most of those plays being "third-and-makeable." The averaged distance needed was 3.83 yards, only one third down required 11 yards to gain, and seven of 12 third-down plays were snapped within three yards of the line to gain.
In Week 15, the difference wasn't about the yardage the Broncos needed on third downs; they needed to gain an average of 7.0 yards, while the Chargers needed 7.17 yards. Thus, the difference in conversion percentage (Denver 22.2 percent; San Diego 50.0 percent) didn't come down to one team being in "third-and-makeable" situations more than the other. The Chargers needed seven yards or less on nine of 12 third downs; the Broncos on seven of nine.
But the Chargers failed on two of the three third-down attempts where they needed nine or more yards, and four of seven when they needed at least seven. Over the course of the season, the Chargers converted 56.3 percent of their third downs when they needed eight yards or less -- but just 29.0 percent when needing nine or more yards.
Thus, the Broncos' defensive hopes on third down rest primarily on their performance on first and second.
"First down, they're getting three yards; second down, they're getting three yards, and they're giving themselves third-and-three, third-and-four, and it's manageable," said defensive tackle Terance Knighton. "When you've got somebody like (Antonio) Gates and (Danny) Woodhead, those guys are capable of getting three or four yards every play.
"So we've just got to limit (Ryan) Mathews on first and second down and not give them any cheap yards or anything like that, and force them into third-and-long. That's when it's easier to get after the quarterback."
And that's when it's easier to get stops of any kind, which will be crucial to preventing the Chargers from the repeated drawn-out drives they mounted on Dec. 12.
