HOUSTON — The Houston Texans have a three-game losing streak. They lost by three in overtime at Dallas, by five at home to Indianapolis and by seven at Pittsburgh.

The Texans were in position to win all three games, but they blew each one with physical mistakes and mental blunders.

If they win at Tennessee on Sunday, they’ll finish the first half of the season with a 4-4 record. That’s what they are — average.

The Texans have enough talent to compete with the better teams, but they don’t play smart enough or well enough from start to finish.

The Texans are their worst enemy. The mistakes are being committed by players and coaches.

For instance, the notorious slow starters scored on a 94-yard drive to lead Pittsburgh 7-0. Then they kicked two field goals to make it 13-0.

Their defense stopped running back Le’Veon Bell, collapsed on quarterback Ben Roethlisberger and ran Arian Foster well enough to force defensive coordinator Dick LeBeau to make several adjustments before he found one that worked.

That was in the first half. The Texans led 13-3 after a Pittsburgh field goal with 3:08 left in the first half.

Then Pittsburgh scored two touchdowns and a field goal to take a 24-13 lead, and there was time still left on the clock before halftime.

“It’s frustrating,” coach Bill O’Brien said. “We’re all frustrated. But I have a strong belief in this team. I believe if we can get this thing headed in the right direction — eliminate turnovers and penalties and not give up big plays on defense — you’ll see a winning team.”

The Texans should be blasted for their second-quarter meltdown but praised for rallying to come within an onside kick of possibly tying the game and forcing overtime.

In the end, they committed three turnovers — fumbles by Arian Foster and DeAndre Hopkins and a Ryan Fitzpatrick interception — that Pittsburgh turned into 17 points.

They also made mental mistakes that left them with bad field position or allowed the Steelers to score easily.

“The two areas that we have to do a better job at?” O’Brien said. “We’ve got to stop turning the ball over, and we’ve got to eliminate the line- of-scrimmage penalties — too many men on the field, offsides, a false start on offense. We can control that, so we have to make sure that we’re correcting it.”

The Texans have been undisciplined at the worst times, but they have also shown mental toughness. It’s kept them in every game but the 30-17 loss at the New York Giants, but Arian Foster didn’t play in that game.

“A team that wasn’t mentally tough would really go in the tank in that situation,” O’Brien said about the collapse in Pittsburgh. “The mentally tough teams that I’ve been around were the ones that fought back and regrouped at halftime.

“Still, we didn’t come out and play our best in the second half, but we certainly showed up in the second half, only giving up two field goals on defense. We did some good things to finally get the game within reach. That’s the sign of a mentally tough team.”

REPORT CARD VS. STEELERS

PASSING OFFENSE: B-minus — Ryan Fitzpatrick was not the reason the Texans lost. He threw an interception that set up a touchdown. He also threw two touchdown passes to go with 262 yards. He helped the offense get off to a fast start and lead 13-0. He helped them rally from a 30-16 deficit with a touchdown pass that made it 30-23, putting them in position to get an onside kick and a possible game-tying scoring drive. But it didn’t happen. The pass protection improved. He was sacked once. DeAndre Hopkins had six catches for 108 yards, but he lost a fumble that set up a field goal in the fourth quarter.

RUSHING OFFENSE: B — Arian Foster reached triple digits for the third consecutive game, finishing with 102 yards and a 5.1-yard average. He had only 14 yards rushing in the second half. The run blocking was excellent in the first half and terrible in the second after the Steelers made adjustments. Foster lost a fumble at the Texans’ 3 that set up a touchdown during the collapse in the last three minutes of the first half.

PASS DEFENSE: D — It was terrific early in the game, but once Ben Roethlisberger got going, he threw two touchdown passes and kept the chains moving. Whitney Mercilus recorded two sacks and a forced fumble. J.J. Watt had a sack and a fumble recovery. Even with pressure, the defensive backs were beaten often and at other times appeared confused.

RUSH DEFENSE: A — The Steelers were ranked fifth in rushing. Le’Veon Bell was second behind DeMarco Murray. The Texans did an outstanding job against the run, limiting the Steelers to 76 yards and 3.0 a carry. Bell carried 12 times for 57 yards, including a 20-yard run. The Texans swarmed to the ball and did their best job of tackling. Led by J.J. Watt and nose tackle Ryan Pickett, they were physical up front.

SPECIAL TEAMS: C — Randy Bullock kicked three field goals. Punter Shane Lechler had a 45-yard gross and a 38-yard net. They downed one of his punts at the 1. Coverage was top notch, but returns were awful. Kickoff returner Danieal Manning made a mistake in the end zone, came out, fumbled at the 1 and put the offense in terrible field position.

COACHING: D-minus — For the first time since the second game of the season at Oakland, the Texans started well on offense, jumping to a 7-0 lead. With superb play by the defense, they increased the lead to 13-0. They led 13-3 with 3:08 left in the first half. The coaching staff should be praised. Then they collapsed in unbelievable fashion, turning that 13-0 lead into a 24-13 halftime deficit. They fought back to make it interesting in the end, but they made too many mental blunders, not to mention physical mistakes. The coaches have to do better.