DETROIT (AP) The Tennessee Titans are already a third of the way to last season's victory total, thanks to Marcus Mariota's poise in the fourth quarter against Detroit.
Mariota's 9-for-9 performance on the winning drive Sunday was an encouraging step for the second-year quarterback, who is trying to help the Titans improve on a three-win season in 2015.
Mariota's 9-yard touchdown pass to Andre Johnson with 1:13 left lifted Tennessee to a 16-15 win over the Lions.
The winning TD came on fourth down.
''I just think we learned some lessons about ourselves,'' Tennessee coach Mike Mularkey said. ''They finished a game and they did it on the road. A lot of circumstances were tough at the end there and I was really proud.''
Mariota competed every pass he attempted during a 13-play, 83-yard drive for the winning points. The Lions, meanwhile, wasted a nice opportunity a week before playing at Green Bay.
Detroit (1-1) was coming off a season-opening win at Indianapolis, but the Lions blew a 15-3 lead in the fourth quarter Sunday.
They also committed 17 penalties for 138 yards. Tennessee was flagged 12 times in a sloppy, disjointed game .
''We need to stop with the infractions, plain and simple,'' Lions coach Jim Caldwell said. ''That's my job. I'll get those guys straightened out in that area.''
Tennessee (1-1) returns home for what figures to be a winnable game next weekend against Oakland. The Titans also have Cleveland and Miami on the schedule next month.
Of course, fans of those teams probably look at Tennessee much the same way - as a chance to pick up a win. The Titans were far from perfect Sunday, and they could have been blown out if it weren't for Detroit's penalties and mistakes.
''We needed something,'' Mularkey said. ''We were really chugging, but we weren't gelling like we needed to until those last couple drives that we needed.''
Johnson's touchdown at the end was his only catch of the game. The 35-year-old receiver has four receptions on the season, and he likes what he's seeing from Mariota, who was dealing with cramping during the second half.
''It doesn't surprise me what he was able to do during that drive,'' Johnson said. ''He's a very tough player, and I knew that he wasn't going to just come out of that game just because he was cramping. He had a great performance.''
The Lions wasted opportunities for more points, but they're getting good production from new acquisitions Marvin Jones and Anquan Boldin. Jones had eight catches for 118 yards Sunday, and Boldin had four receptions for 48 yards, including a 24-yard touchdown.
If those two can keep that up, Detroit's passing game should be in solid shape even after losing Calvin Johnson to retirement.
Tennessee's DeMarco Murray had 89 yards on only 12 rushing attempts. If you take out a 67-yard run, that's not a great average, but he also added a team-high seven catches for 56 yards.
Ameer Abdullah and Theo Riddick were impressive in the season opener for the Lions, raising the possibility that Detroit's running game could be much improved this season.
Sunday wasn't as good a showing. Abdullah had 38 yards on six carries, but left late in the second quarter with a foot injury. Riddick was held to 37 yards on 11 carries.
''Tennessee's got a really good defense, did a nice job of being physical,'' Lions quarterback Matthew Stafford said.
''But we had a bunch of yards and a bunch of points taken off the board from penalties and mistakes on our end. So that's something we can't do.''
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