Afterward, Sumlin addressed the racist hate mail he received at his home this week, a letter made public by his wife, Charlene, in a tweet she posted Thursday. It read: "You suck as a coach! You're a n----- and can't win! Please get lost! Or else."
Asked about the letter following Saturday night's win in College Station, Sumlin said the hate mail crossed a line.
"I get criticism, which is part of the job. I get suggestions, and that's part of the job," he said. "In this situation, for that [letter] to come to my home and for her to open it and read that, that is completely different. My wife and kids have never called a play. My wife and kids have never done anything footballwise that led to us losing a game or winning a game.
"The racial [aspect] is one part of it, but the open-ended threat at the end, [sent] to my house ... I've got to draw the line there."
Charlene Sumlin posted a statement on Facebook on Sunday discussing her decision to go public, as well as expressing gratitude to those who have sent her family kind messages of support in the days since the letter arrived.
"THANK YOU for the literally hundreds of text messages, phone calls, private messages etc.," she wrote in the statement. "I couldn't respond to everyone, I started to try at first and then it just became so overwhelming, but I want everyone to know that I read them and I am so grateful for the love and support."
She also confirmed in the statement that authorities are investigating to learn who sent the letter.
"I literally cannot wait to look at this person eye-to-eye," she said. "There is a unique kind of cowardice in someone to anonymously criticize, ridicule or threaten another person. If I have the opportunity to expose even ONE troll. I am going to do it."
Sumlin has faced heavy criticism since Texas A&M's season-opening loss last Sunday at UCLA, in which the Aggies blew a 34-point third-quarter lead. Texas A&M regent Tony Buzbee called for Sumlin's immediate dismissal in a Facebook post he published shortly after the game.
While the Aggies evened their record Saturday night, it wasn't easy. Nicholls, an FCS school that plays out of the Southland Conference, tied the game at 14 in the fourth quarter before Texas A&M scored 10 unanswered points.
"By no means are we where we need to be,'' Sumlin said afterward.
As for the letter, the Brazos County (Texas) sheriff's office announced earlier this week that it has an open investigation into it. Sumlin, one of seven African-American head coaches in a Power 5 conference, said he's appreciative of their efforts, as well as the support he has received all week.
"I want to thank the Brazos County sheriff's office for what they're doing right now, and I want to thank all the people who sent me notes and text messages and calls and things like that. That's important, too," he said.
"When you cross a line like that, with people who have nothing to do with decisions that are made when it comes to my job, that's not OK."
Information from ESPN's Adam Rittenberg was used in this report.