Whitney Mercilus snared the first interception of the season for the Texans defense.
He also logged the Texans' first sack of 2019.
Mercilus caused trouble for Drew Brees and the Saints, adding in a tackle for loss and five total tackles.
Ultimately, it came in a back-and-forth ballgame that resulted in a 30-28 Texans defeat.
"Brees happened, we happened," Mercilus said. "We've just got to be able to get a stop."
Late in the first quarter, with the Texans' defense backed up in the red zone, Mercilus picked off a Drew Brees pass intended for Latavius Murray at the 4-yard line. He returned it two yards.
It ended what was an 8-play drive that lasted 4:02, and set Deshaun Watson and the offense up with a 1st-and-10 at the 2:55 mark. Watson and the Texans would score on that drive to take a 7-0 lead early in the second quarter.
"I just undercut the route and picked it off," Mercilus said. "I knew Brees was going to hit the back because it seemed like he was free."
With just over nine minutes left in the fourth quarter, Mercilus dropped Brees for a loss of eight yards. It forced the Saints into a 3rd-and-19 situation, and they wound up punting on fourth down.
"He's a good player," head coach Bill O'Brien said. "He's shown that in all those years here. He had a good game."
After allowing New Orleans just three points in the first half, the Saints erupted for 27 after the intermission.
"There was just a play here, a play there, especially in the second half," Mercilus said. "We've got to be able to play better."
Mercilus and the Texans host the Jaguars on Sunday at NRG Stadium.