One week after becomnig the NFL's all-time leading rusher, Dallas' Emmitt Smith gained just 39 yards and also missed a block on a blitzing linebacker that led to a fumble by quarterback Chad Hutchinson and a Detroit field goal.
Hanson also made kicks from 42 and 44 yards in the third quarter before Dallas took the lead on a three-yard touchdown run by Troy Hambrick with 7:42 remaining in the fourth.
Hambrick's touchdown capped a 12-play, 80-yard drive that was the Cowboys' lone offensive burst of the game. Hutchinson was five of six for 66 yards on the drive, but was 17 of 33 the rest of the day for 142 yards. He was also sacked five times as the Cowboys' offensive line struggled without Larry Allen, who sat out with an ankle injury.
"I don't think I'm frustrated with the offense," Smith said. "I just don't think we've done enough to be productive. We just have to do more to be focused. We don't do all the things we're capable of doing."
The Dallas offense generated 226 yards in the game, but that was still 77 more than the Lions managed.
Running back James Stewart led the Lions with 50 yards rushing and 41 yards receiving. His 12-yard catch on fourth and three to the Dallas 31 kept the winning field goal drive alive.
The teams combined for 122 rushing yards, averaging 2.4 yards per carry.
It was the second time in three weeks that the Cowboys lost a game in which they did not surrender a touchdown. Detroit improved to 3-5 and the Cowboys slipped to 3-6.
"I won't say I like situations like this but I don't hate them," Hanson said of his winning field goal. "I'd rather have us up three or four touchdowns and be smiling on the sidelines instead of sweating bullets. But this is part of the game and I work hard during the week to prepare for it."
"We're struggling on offense but it's a matter of execution," Detroit coach Marty Mornhinweg said. "We have a lot of work to do."
"We didn't run the ball effectively as we would have liked," said Dallas Coach Dave Campo. "The key to us is getting as health as we can over this break that we have."
Dallas has a bye week coming up. Seven of the Cowboys' nine games have been decided by fewer than five points. Dallas is 2-5 in those contests.
With their third win of the season, the Lions exceeded their win total from last year. Detroit has also won three straight home games since losing the opening game at Ford Field to Green Bay in September. The Lions last had a three-game home winning streak in 1999, when they won five straight at the Pontiac Silverdome and made it into the playoffs with an 8-8 record.