By Greg Gabriel–

(CBS) It was reasonable to believe that the Bears could be clearly improved this season and yet still lose their first four games of the season, given their tough schedule to start. I was one of those individuals.

Well, we were wrong. The Bears outperformed the physical and talented Steelers in a 23-17 overtime win at Soldier Field on Sunday to improve to 1-2.

Until Sunday, the Bears hadn’t won a game in September in the John Fox era. Chicago controlled the first half and easily could’ve been up 24-7 at halftime, given that kicker Connor Barth missed a 47-yard field goal and cornerback Marcus Cooper failed to run through the end zone for a touchdown with the clock expired and instead was stripped of the ball on a wild play. Instead, Chicago was up 17-7 at halftime after converting a field goal on an untimed down to end the half following a Pittsburgh penalty on Cooper’s gaffe.

In the second half, the Bears tried to give the game away by turning the ball over twice deep in their own territory and letting the Steelers tie the game at 17-17. But the Bears responded in overtime with a 74-yard drive in four plays, all on the ground.

It was an unusual win, as the Bears only had 84 net yards passing but also an astonishing 220 rushing yards against one of the better defenses in the NFL. The Bears defense is what won the game, holding the high-octane Steelers to 282 yards of total offense.

The game wasn’t without some big-play performers, and that’s what’s important to point out in this win.

The player who has shown more improvement than anyone on the Bears defense is cornerback Kyle Fuller. Going into training camp, most considered Fuller as a player who would be cut or traded because of both his performance and lack of durability over the last two seasons.

Sunday may have been the best game Fuller played as a Bear. Not only did he play well with tight coverage and pass breakups but he was more physical than I have ever seen him. He had one hit on Steelers tight end Jesse James that was likely his best hit in his entire four-year career. Fuller is playing like we would expect a 2014 first-round pick to play.

While Cooper had the boneheaded play at the end of the first half that could have cost the Bears the win, his play at the cornerback opposite Fuller was excellent. He also played tight in coverage, supported the run and played the ball well. The Bears’ cornerback play Sunday was the best since Vic Fangio became defensive coordinator in Chicago.

Linebacker Pernell McPhee has missed a lot of time the last two years because of knee injuries and he may never be the player we saw in his first year with the Bears, but in limited action, he provided a strong pass rush, including getting a key sack on Ben Roethlisberger. The fact is when McPhee is on the field, the Bears defense plays better.

Center/guard Cody Whitehair is quickly becoming the Bears’ most valuable offensive lineman. He started the game out at left guard then had to move to center when Hroniss Grasu injured his right hand. Whitehair played excellent football at both positions and was one of the reasons the Bears ran for 220 yards.

What can you say about second-year running back Jordan Howard? He left the game three times because of a shoulder injury, yet he kept coming back, and it was his determined running ability that won the game. He wasn’t going to be denied on the game-winning 19-yard touchdown run in overtime. To say Howard was playing with pain is an understatement, and he deserves NFC Offensive Player of the Week honors.

Rookie running back Tarik Cohen is a backup who’s supposed to be just a role player, but in three games he has shown he may be the most valuable offensive player on this Bears team. He may measure only 5-foot-6, 185 pounds, but he plays far bigger than his measured size. And his speed, running instincts and elusiveness are rare. He also has a competitive nature second to none. His 36-yard run in overtime set up the touchdown by Howard, and his elusiveness had Steelers tackling air. He’s quite a performer.

It’s a short week for the Bears, who face the Packers at Lambeau Field on Thursday evening. If the Bears can continue to come up with as many big plays as they did Sunday and limit their mistakes, they could be 2-2 and in the thick of the NFC North race come Friday.

Greg Gabriel is a former NFL talent evaluator who’s an on-air contributor for 670 The Score. Follow him on Twitter @greggabe.