He caught an 11-yard pass from quarterback Kyler Murray on the game's second play, earning him a standing ovation from the home crowd inside State Farm Stadium just nine days after joining the Cardinals via trade from the Philadelphia Eagles.
Ertz's Cardinals debut, a 31-5 win over the Houston Texans, couldn't have gone much better. He caught three of his five targets for 66 yards, which tied for the team-high. He also caught the longest touchdown of his career, a 47-yard catch-and-run that traveled just 18 yards in the air.
The trade that sent Ertz to Arizona from the Eagles was announced the morning of Oct. 15, a Friday, even though Ertz knew about it earlier in the week. He flew to Arizona on a private plane after playing in the Eagles' Thursday night game the day before.
He then flew with the Cardinals to Cleveland, even though he wasn't eligible to play in the Week 7 game against the Browns. Ertz was seated next to Murray on the plane, a decision that Ertz is convinced came from the front office and wasn't just a coincidence. The two talked football and life, getting to know each other as much as they could.
During the rest of the week, Ertz dove into the playbook with the help of Julie, who, Zach said, quizzed him on plays. Zach knew if he could understand the offense enough to play fast against Houston, he could excel in it.
He got some help from Murray, and the rest of the offensive players and staff with the hand signals that accompany Arizona's playcalls.
"He had a quick week, but he learned it quickly," Murray said.
Adding another playmaker in Ertz only bolsters the 7-0 Cardinals' chances of making this season special. Defensive coordinators will be forced to decide who to cover between a strong pass-catching core that now includes DeAndre Hopkins, A.J. Green, Christian Kirk, Rondale Moore and Ertz.
"I think we got a lot of talent, obviously," Ertz said after the win over Houston. "I've never seen so much green grass in the middle of the field, and that's gonna happen with a guy like DeAndre Hopkins and A.J. Green on the outside, and a quarterback like Kyler.
"Not everyone's going to go off each and every week and everyone's got to be OK with that because the ultimate goal is to win a football game."
Coach Kliff Kingsbury said Ertz -- and his Stanford education -- deserved credit for picking up so much of the offense during such a short time period. It's even more impressive considering Ertz couldn't just walk up to Kingsbury and ask him questions. Kingsbury tested positive for COVID-19 the afternoon that Arizona traded for Ertz. The two talked and texted all week but met for the first time pregame Sunday.
Kingsbury liked what he saw.
"He's a tough matchup for linebackers and when you've got some of the guys that we've got outside, it definitely helps," Kingsbury said.
With the Cardinals on a short week before a matchup against the Green Bay Packers on Thursday, Ertz will prepare for his second Thursday night game in three weeks. Once that's over, he'll have a chance to take a deep breath.
But he's already made an impression.
"His down-the-field, middle-of-field presence, I feel like those, those are things that he brings to this team," Hopkins said. "[Tight end] Maxx [Williams] and those guys are good, but Zach is a Pro Bowl tight end and, so, to be able to have that presence in the middle of the field, that helps out a lot."