HOUSTON– Sometimes the margin of error for a cornerback is so small it is barely noticeable.
Its turning his head around a second too late; an outstretched hand in a defender's face; or jamming a receiver's inside shoulder instead of the outside. Sometimes it is those missteps that lead to a big reception -- or touchdown.
Against elite NFL receivers those mistakes get magnified. That was the case for Dolphins cornerback Sean Smith who allowed Andre Johnson to score a 14-yard touchdown in the final 12 seconds of the second-quarter of Sunday's 30-10 loss.
Smith, who is in the final year of his rookie contract, was so bothered by his performance on Johnson's score he punched his locker upon leaving the Texans locker room.
"On that touchdown I turned my head back way too late," Smith said. "When I turned my head back late the ball was behind me."
And placed in a beautiful spot by quarterback Matt Schaub, where only Johnson could have caught the first down pass, which came two plays after the Dolphins' third straight turnover in that quarter's final five minutes.
Johnson, whose average yards per game (79.5) is the highest in NFL history, hawked down the pass and tiptoeing inside the edge of the end zone to give Houston a 24-3 lead.
"I know what I'm capable of doing," said Johnson, who caught eight of the 10 passes thrown his way for 119 yards and a score. It was his 39th 100-yard game in his 10 seasons.
The former University of Miami standout's biggest reception came on a 29-yard grab in the third quarter, where he beat safety Jimmy Wilson, who was filling in as Miami's fourth cornerback.
"I just go out and make the most of my opportunities," Johnson said.
Smith didn't have many opportunities to cover Johnson, who primarily works on the opposite side of the field. But coach Joe Philbin was critical of the one instance where the team's top cornerback was on duty.
"I'm disappointed on the last play of the half. They scored with 12 second left on the clock, they didn't have any timeouts," Philbin said. "You know the ball is going into the end zone. That's not good football."
Johnson wasn't the only Texan doing big things against Miami's defense, which allowed 337 yards. Tight end Owen Daniels caught four of eight passes thrown his way, contributing 87 of Schaub's 266 passing yards.
"This film is going to be tough to watch," Smith admitted. "The first half we came out on all cylinders. We were stopping the run and getting them off the field. Then we dug a hole for ourselves and it went downhill from there."
Smith's referring to the three back-to-back turnovers that closed the first half. The Texans turned thought three turnovers into two rushing touchdowns from Arian Foster and then Johnson's 14-yard score.
"You have to get your hands on him early," said new Dolphins safety Troy Nolan, who spent the past two seasons practicing against Johnson as a member of the Texans, and passed on his tips to his new teammates. "Andre can't get a free release on the ball. You have to get your hands on him and disrupt him any way you can.
"Watching film doesn't tell the whole story. He's been doing great things in this league for a long time, playing at a high level. There is nothing a player like that can hide."
And also nowhere a defender covering him one-on-one can hide. That's certainly been the case for the Dolphins considering Johnson's caught 45 passes for 638 yards and scored five touchdowns in the six games he's played against the Dolphins, all of which have resulted in wins.
"If you're a competitor you definitely want to go against a great receiver," said Smith, who was on Johnson the two times he didn't bring in balls thrown his way. "I'll see him again."