Chad Henne's prettiest pass of the day was wiped out by a miscommunication involving a backup tackle and the referee.
Hapless as ever, the Jacksonville Jaguars had two touchdowns taken off the scoreboard, got stopped three times on fourth down and lost Henne's homecoming game to the Miami Dolphins, 24-3.
Amid a flurry of Jacksonville mistakes, one loomed as the turning point Sunday. With the score tied in the second quarter, an illegal-substitution penalty cost involving tackle Guy Whimper cost the Jaguars a TD.
"Definitely a frustrating day," running back Montell Owens said. "It's always frustrating when you don't win a ball game. A lot of it was self-inflicted."
Miami (6-8) won for only the second time in the past seven games. The Jaguars (2-12) only helped their chances of getting the No. 1 draft pick next April.
"We were not as disciplined as we have been - or we will be," Jacksonville coach Mike Mularkey said. "Every time we take a step forward, we take two steps back. I take total blame for that."
Henne, playing in Miami for the first time since he departed as a Dolphins bust last offseason, threw for 221 yards with no turnovers. But he was outplayed by counterpart Ryan Tannehill, who had a season-high rating of 123.2.
Tannehill went 22 for 28 for 220 yards and two scores with no interceptions, and he ran eight times for 52 yards. Reggie Bush rushed for 104 yards, including a 53-yarder to set up a field goal.
Jacksonville appeared to take a 10-3 lead when Henne threw a 20-yard scoring pass to Justin Blackmon. But the play was negated because Whimper had entered the game as a third tackle - as he had done five times earlier - without reporting as an eligible receiver.
"He reported to the offense a hundred times this year, and 400 times in practice," Mularkey said. "Today, for some reason, I was told he didn't report. He said he reported, but the official has to confirm it."
Whimper said he was shocked to be penalized for the way he entered the game.
"I do it every day, I don't see how this time was different," he said. "He probably just looked past me or was looking in my direction but not at me."
Instead of the score, the Jaguars retreated to their 25 and eventually lost possession when Henne was stopped for no gain on a fourth-and-1 sneak.
"That turned the whole game around," Miami linebacker Karlos Dansby said.
Jacksonville had another touchdown taken off the board in the final two minutes. Cecil Shorts' 4-yard scoring reception was instead ruled incomplete when a replay review determined he failed to come down in bounds.
On the next play, Henne threw incomplete on fourth down.
"It was one of those days where it was tough," Henne said. "There are some plays out there I wish I could have back."
Jacksonville had the ball for just 14 minutes in the final three periods. The Dolphins' first four possessions of the second half resulted in clock-eating drives of 76, 60, 64 and 85 yards.
"That was a poor job by us defensively," Jaguars linebacker Paul Posluszny said. "We fought hard the entire first half, then we give up a couple big plays and don't get off on third down."
The Dolphins' first touchdown came when they converted three third downs in a 14-play, 89-yard drive that ended with Tannehill's 4-yard scoring pass to fullback Jorvorski Lane. Tannehill went 6 for 6 on the drive.
Leading 10-3, the Dolphins tried a fake field goal at the Jacksonville 5, but holder Brandon Fields' pass fell incomplete. Miami quickly forced a punt, and Bush's long run set up another field-goal situation. This time, Dan Carpenter kicked a 30-yarder.
Dansby stopped Henne on fourth down at the Miami 11, and Jason Trusnik tackled Owens for no gain on fourth and 1 at the 15 early in the fourth quarter.
"Those plays were momentum-gainers," Dansby said. "They took chances. We had to step up and get them off the field."
The Dolphins sewed up the victory with an 85-yard drive that took nine minutes of the fourth quarter and ended with Tannehill's 2-yard touchdown pass to Anthony Fasano.
NOTES: Miami CB Nolan Carroll (left knee) and TE Charles Clay (right knee) were hurt in the second quarter. ... The 1972 Dolphins, celebrating the 40th anniversary of their perfect season, were honored at halftime. ... Miami's Brian Hartline surpassed 1,000 yards receiving for the first time. ... Blackmon had six catches to increase his season total to 51, the most by a Jaguars rookie.