SEATTLE -- Several minutes after the final whistle of the Seattle Seahawks' season-opening victory Monday night, Geno Smith walked off the field with his arms raised to the sky and what remained of the home crowd chanting his name.

So much for Russell Wilson getting the hero's welcome in his return to Lumen Field six months after his trade to the Denver Broncos. It was Smith who got the loudest ovation and the upset victory over the quarterback he used to back up.

Making his first opening day start since 2014 with the New York Jets, Smith threw a pair of first-half touchdown passes and avoided costly mistakes. Add to that a stellar defensive effort and a missed Denver field goal in the closing seconds and it proved to be enough for the Seahawks in their 17-16 win over the Broncos, who were 6.5-point favorites.

"They wrote me off," Smith told ESPN's Lisa Salters postgame. "I ain't write back, though."

Smith's eight seasons was the longest stretch between Week 1 starts by an NFL quarterback since 1971, according to the Elias Sports Bureau. In between, he has suffered a broken jaw via a locker room sucker punch that cost him his starting job with the Jets and a torn ACL before backing up three of the most durable quarterbacks in NFL history in Eli Manning, Philip Rivers and Wilson.

After an up-and-down summer in which he held off Drew Lock to win Seattle's quarterback battle, Smith looked the part of an NFL starter Monday night -- particularly during his nearly flawless start. He completed his first 13 attempts and finished the first half 17-of-18 for 164 yards and two touchdowns.

According to ESPN Stats & Information research, Smith's 94% completion rate tied Matt Hasselbeck (Week 11 of 2010) for the best by a Seahawks quarterback in any half since 2000 (minimum of 15 attempts).

"How about Geno?" Seattle coach Pete Carroll said postgame. "I mean ... 17-for-18 in the first half. Who does that? Guys just don't do that ... Geno played tonight like he has been playing the whole time we've been practicing. That's what he has been looking like. He didn't look any different than what he has looked like in practice.

"That's why we had the belief in him, and that's why he was able to win the job and go out there on Monday Night Football and win the football game."

While Seahawks fans booed Wilson loudly and relentlessly, they celebrated Smith's big plays with chants of "Geno, Geno" -- just like last season, when Smith replaced an injured Wilson during an October loss to the Los Angeles Rams and promptly led a touchdown drive.

On Monday night, there were plenty of big plays to celebrate.

On Seattle's opening drive, Smith avoided a sack and floated a ball to a wide-open Will Dissly for a 38-yard touchdown. His second scoring pass -- a 25-yarder to fellow tight end Colby Parkinson -- came on a perfect throw up the seam. Smith made plays with his legs too, like his 14-yard scramble run at the end of the third quarter and a designed quarterback sweep to convert on third-and-2 on the next play. The latter run prompted Carroll to emphatically shoot his arm forward to signal first down.

Smith finished 23-of-28 passing for 195 yards and no turnovers. He lost the ball on one of his two sacks, but left tackle Charles Cross recovered it. Smith also added 14 yards on six carries.

"He made more plays with his legs than I expected him to tonight," Carroll said. "He took off, and I was so mad at him the time he was running up the sidelines and got smoked on their sidelines. What's he doing? Get down. I got over it ... Just finding Diss on the first touchdown pass, escaping the rush, slipping up underneath and dumping the ball for an easy touchdown. Gorgeous play by him. He had some other ones, as well. You can see.

"I don't know if you guys were doubting or everybody thinks that we were making stuff up. We weren't. This is what he looks like. Obviously, he just did it again. Anyway, you can think whatever you want."

Smith backed up Wilson the past three seasons and went 1-2 last year while Wilson was sidelined with his finger injury. The two shared a warm exchange before and after the game.

"Just a lot of love," Smith said. "I got a lot of respect and love for Russell. Being here with him for three years, I learned a lot, got to know him really well, got to understand why he is the man that he is, the way that he is and what makes him special. Russell will always be my brother. I love him to death, and I just wish him the best."

Seattle's offensive struggles during its scoreless second half gave Wilson a chance to pull off another late comeback, something he did so many times in his 10 seasons here. The Seahawks' first three possessions resulted in a fumble and two punts. Their fourth and final possession was a kneel-down after Denver took the ball out of Wilson's hands and missed the field goal try from 64 yards out that would have won the game.

"We have to be better in the second half," Smith said. "That's all I was thinking about, honestly. I felt like in the second half -- obviously their defense, give credit to their defense. They stood up and played well, but we've got to finish games better. It's great to get a win. Our defense went out there and did what they had to do, but we could have put up more points and given ourselves an even more cushion to have a better shot in that game."

The Seahawks, widely projected to finish last in the NFC West, were the only team in the division to win in Week 1.

Smith shot down the idea of feeling personally validated by the victory.

Carroll was asked how gratifying it must be for Smith given everything he has gone through in his career.

"I would think very much so," Carroll said. "I'm saying it and I don't care if anybody believes this: He's the best he's ever been. Because of the four years of being in the system and being loved up and taken care of and looked after -- and he did his part, in reverse, to always be there for us -- he's ready. He's ready for this moment ... He was so poised and calm in this game. It was just fun playing with him.

"We were talking as the game is going on, and he is having fun and laughing and enjoying it. The moment came to him, and he was ready for it. That's a really beautiful illustration. It's a great story. I think it's a great story."