COSTA MESA, Calif. -- NFL observers rightly questioned whether the Los Angeles Chargers had enough firepower on defense to compete with the best teams in the league after a 1-2 start.

The Chargers allowed just 17.4 points per game in 2017, third-best in the NFL. However, through three games this season, the Chargers were giving up a humbling 31 points a contest, second-worst in the league.

Those first three games, the Chargers allowed 19 explosive plays -- runs of 15-plus yards or passing plays of 20 or more yards -- tied for fifth-most in the league.

But those two losses came to the Kansas City Chiefs and Los Angeles Rams, offenses we know to be juggernauts, and Chargers slot defender Desmond King said the slow start helped serve as a wake-up call for the defense.

"From that point on, we said, 'We're going to stop the explosive plays,'" King said. "If we can stop the explosive plays, our defense can be so much better and the games will be in our advantage. And that's what we've been seeing throughout the season as we've stopped passes going over our heads."

King's right. Now riding a six-game winning streak, the Chargers have held teams to 15.5 points per contest, tops in the NFL during that stretch.

Along with that, the Chargers allowed just 28 explosive plays over the past six games.

Well, how have they done it? Here are four things the Chargers are consistently doing as they've staked out a 7-2 record.

Stingy in the red zone

The Chargers also are No. 1 in red zone efficiency since Week 4, at 33.3 percent, and they've had impressive goal-line stands in the past three games.

The defense kept Marcus Mariota and the Tennessee Titans' offense from converting a two-point conversion that would have won the game for Tennessee in London in Week 7.

The Chargers stopped the Russell Wilson-led Seattle Seahawks from scoring a touchdown that would have potentially sent the game into overtime at CenturyLink Field in Week 9.

And Sunday against the Oakland Raiders, safety Derwin James sniffed out a shovel pass to Dwayne Harris on fourth down on the team's opening drive, shutting down Oakland's momentum early.

"We always talk about, if it's on the 1-yard line, give us an inch and we'll protect it," Chargers defensive coordinator Gus Bradley said. "That's more our mentality as a defense in those situations. ... Give us two inches and we'll protect it. So to go out there and compete, and to come together and make a play, you know, it's great to show the players that mindset."

Taking the ball away

One of the main principles head coach Anthony Lynn and Bradley preach is getting after the football. And during their six-game winning streak, the Chargers have done a much better job of taking the football away.

The Chargers have a plus-6 turnover differential during the streak, forcing nine turnovers in six games.

Philip Rivers and the Chargers' offense have converted those opponent miscues into 28 points, fourth-most in the NFL over that time.

During the Lynn era, the Chargers are 11-3 when they force at least two turnovers in a game.

With Joey Bosa out due to a bruised left foot, it took some time for the Chargers to figure out how to create consistent pressure up front. But after recording seven sacks through three games, the Chargers have 19 since Week 4, including eight on third down.

A more effective pass rush has helped the Chargers get off the field and keep teams out of the end zone. The Chargers have allowed a league-low eight offensive touchdowns since Week 4.

Playing from ahead

The Chargers have trailed a total of 60 minutes in the past six games, holding leads going into halftime in five of those six.

The Chargers have outscored opponents 147-89 in the first half this season.

Last season, the Chargers trailed at halftime in six of the team's 16 games and were outscored 66-44 in the opening quarter.

So playing from ahead has helped the Chargers continue to be more balanced and aggressive on offense, and allowed the defense to be just as aggressive in getting after the opposing team's offense.

"That's something that we put an emphasis on," Lynn said. "We want to play from ahead. Last year we played from behind a lot. We're trying to start with more urgency this year, playing from ahead.

"It can benefit your pass rush, I can tell you that. You force teams in obvious situations where you've got to pass the football, our guys get a chance to come off the ball and tee off a little bit."

Playing with energy

Melvin Gordon says he's an energy guy. His first two seasons with the Chargers, Gordon said he could sense in the locker room that things weren't great from an energy standpoint, and it showed on the field.

The Chargers finished 4-12 and 5-11 during Gordon's first two seasons, so he's not taking this one for granted.

"It's just dope, man, because I'm enjoying winning," Gordon said. "I'm not going to lie to you. On the plane rides back -- in previous years, guys were quiet on the plane and guys were in their own world. It's a different type of energy that's not good."

Winning has changed players' attitudes at the facility. Since starting last season 0-4, the Chargers are 16-5, the fifth-best record in the NFL over that time frame.

The energetic, enthusiastic play of the defense has a lot to do with the team's success.

"We're having a lot of fun," safety Jahleel Addae said. "It's what we love to do. I think you can see that. It doesn't matter who gets the play on the ball. It could be a linebacker, it could be a forced fumble by a defensive lineman. It doesn't matter. Whoever makes that turnover, we're going to take it."

Added Gordon: "Looking at those guys sometimes, I'm like, 'Man, I can't loaf today.' They're depending on me. I'm depending on them. We have to go get it. That's just the mindset."