Tannehill threw two touchdown passes and the Dolphins turned back several St. Louis scoring threats, including a 66-yard field goal try by rookie Greg Zuerlein that sailed wide left on the final play. Miami won despite being outgained 462 yards to 192.
''We know how football is played,'' Dolphins receiver Davone Bess said. ''It's not about statistics; it's about winning. Pretty, ugly, it doesn't matter. It's just about winning.''
The Rams scored their lone touchdown with 8 1/2 minutes left, then moved 49 yards to face a fourth-and-7 at the Miami 48-yard line with 30 seconds left. Rather than go for a first down, coach Jeff Fisher sent out rookie Greg Zuerlein to try a 66-yard field goal — which would have been an NFL record by 3 yards.
The kick appeared to have enough distance but missed wide left, leaving both teams at 3-3.
''I can make that kick. I just didn't come through,'' Zuerlein said. ''I came across the ball a little bit. I should have made it.''
He has made four kicks of 54 to 60 yards this season.
''The odds were much better for him to make the kick than us going for it,'' Fisher said. ''He's got that kind of leg."
Zuerlein made his first two field goals to improve to 15 for 15 this season, then missed three times in a row, including wide left from 48 and 32 yards in the first half.
Tannehill went 21 for 29 for 185 yards with no turnovers. The rookie threw touchdown passes of 29 yards to Marlon Moore and 1 yard to Anthony Fasano.
But the Dolphins were outrushed 162-19, and Sam Bradford went 26 for 39 for 315 yards for the Rams, who struck for early gains of 44 and 65 yards. At halftime, St. Louis had outgained Miami 294-99 but trailed 10-6.
''We had a lot of opportunities to win this game, but we didn't get it done,'' Fisher said. He lost to the team that courted him in January, when he chose the St. Louis job instead.
The Rams were down 17-6 before they finally got into the end zone when Bradford scored on a 1-yard sneak on fourth down. He juggled the ball as he held it over the goal line, but the call was upheld following a review.
Bradford then hit Steven Jackson with the 2-point conversion pass to make the score 17-14.
Two other key reviews also went against the Dolphins. They led by 11 points and appeared on the verge of pulling away when they recovered a fumble by Bradford on a sack midway through the third quarter. But the turnover was negated by a review, when the officials ruled the play an incomplete pass.
On the Rams' next possession, Chris Givens lost a fumble after a short catch, but again the ruling was changed to an incompletion following a look at the replay.
Daryl Richardson's 44-yard run set up the Rams' first field goal, and Givens beat the Miami secondary deep for a 65-yard reception to set up another field goal for a 6-0 lead.
The Rams came away empty from two other trips into Miami territory in the first half.
''When they get into the red zone, our thinking is three points or less,'' cornerback Sean Smith said. ''A touchdown is not an option.''
Moore, a backup who came into the game without a catch this season, put the Dolphins ahead to stay when he slipped behind Janoris Jenkins for his first touchdown catch since 2010.
Rams fullback Brit Miller fielded a short kickoff and lost a fumble, setting up a Miami field goal. A 62-yard touchdown drive to start the second half put the Dolphins ahead 17-6.
But they often found it difficult to block the Rams. The offensive line was flagged for four penalties — one declined — during an especially unsightly sequence.
Miami's Brian Hartline, who came into the game leading the NFL in receiving yardage, was held without a catch.
''It wasn't pretty,'' Tannehill said. ''It was pretty disappointing the way we played, especially in the first half. But we stuck together, hung in there and got it done.''