It could've been in Week 1, when he played 19 days after knee surgery and broke Steve Largent's record for receiving yards in an NFL debut with 89 yards against the Cincinnati Bengals. Or midway through the year, when he went for a season-high 123 yards and a touchdown against the Tampa Bay Buccaneers, giving him three scores in two weeks. It might not have been until the wild-card round, when his 160 yards (plus a touchdown) against the Philadelphia Eagles set an NFL playoff record for a rookie in the Super Bowl era.
Or maybe it was a month earlier, during an otherwise forgettable 16-point loss to the Los Angeles Rams. Metcalf caught six passes for 78 yards that night, but it was less about his overall numbers and more about the fact that he did most of it against All-Pro cornerback Jalen Ramsey.
Round 2 earlier this season was a decisive victory for Ramsey and the Rams, who shut down Metcalf in their win over Seattle. Round 3 comes Sunday when the Seahawks (10-4) host Los Angeles (9-5) at Lumen Field (4:25 p.m. ET, Fox) with a chance to win the NFC West.
If nothing else, the initial matchup last December gave Seattle the first indication of how Metcalf would respond to getting star treatment from an elite corner, which he has done with mostly positive results.
According to NFL Next Gen Stats, Ramsey lined up across from Metcalf on 29 of his 31 routes in last year's game, with Metcalf catching all five targets from Russell Wilson for 69 yards when Ramsey was the nearest defender in coverage.
"Jalen matched him early; we didn't try him a whole lot," offensive coordinator Brian Schottenheimer recalled. "As the game went, Russ found him on a big scramble play, there was some other plays that we got to him. So it was at that moment you're like, 'OK, this guy wants the ball in those situations, he wants to be great.' That continued to grow into the playoffs.
"You watch him in Philadelphia, what he was able to do in that situation. So you knew pretty quick that that was a guy that, 'Hey, I want the spotlight, I want the ball, give me an opportunity to make those plays no matter who I'm up against.'"
Metcalf has followed up his 900-yard rookie season with 1,223 yards through 14 games this year -- third-most among receivers -- to earn a Pro Bowl nod. Arguing he belongs in the NFL's upper tier of his position is easy given what he's done against some of the league's best corners this season, starting with the New England Patriots' Stephon Gilmore in Week 2.
According to Next Gen Stats, the NFL's reigning Defensive Player of the Year was lined up across from Metcalf for 26 of the 30 routes he ran. Metcalf caught three of five targets for 85 yards --- including a 54-yard touchdown -- when Gilmore was the nearest defender in coverage.
Since then, Metcalf's numbers when other notable corners were nearest him in coverage include:
And then there was what Metcalf did against Philadelphia's Darius Slay last month. He lined up across from Slay on 26 of his 27 routes and caught seven of 10 targets for 141 yards, the second most by a receiver against a defender this season.
Gilmore was just named to his fourth Pro Bowl and is a two-time All-Pro. Howard and White (an All-Pro last year) were named to their second Pro Bowls, Bradberry his first. Slay (an All-Pro in 2017) had his streak of three straight Pro Bowls ended.
"If teams want to match him with somebody, they do," Schottenheimer said. "... The defense is out there to try to slow us down and to present problems for us, but we don't ever give them too much credit. We don't ever say, 'OK, well, if this guy matches you, we can't throw you the ball.' DK's too good of a player to have that happen."
Metcalf was asked after the most recent Eagles game what he thinks when he knows he's going to get a lot of attention from an opposing defense and its best corner.
"I'm happy," he said. "I'm getting a little respect, but I've still got work to do."
That's when he revealed Eagles defensive coordinator Jim Schwartz had ticked him off pregame with a comment referencing Calvin Johnson, an intended compliment Metcalf took as a slight.
Here's the video of DK Metcalf talking about the pregame incident with #Eagles' DC Jim Schwartz. Metcalf says Schwartz told him: "I was in Detroit with Megatron but you're not there yet."— NFL Update (@MySportsUpdate) December 1, 2020
"He's a guy that's always responded, whether it's a guy matching him or people challenging him saying you can't do this or you can't do that, or hey, his draft status a couple years back, it motivates him," Schottenheimer said.
Arizona's Patrick Peterson is the glaring exception to the success Metcalf has had in high-profile matchups. He has yielded three catches on eight targets for 27 yards to Metcalf in three games, though Wilson didn't have much need to look Metcalf's way in Week 7 with Tyler Lockett having a career night.
And Ramsey got the better of Metcalf in Week 10, lining up across from Metcalf on 30 of his 42 routes and holding him without a catch on either of his two targets when Ramsey was the nearest defender in coverage. Metcalf's two catches in that game tied his season low while his 28 yards were his second fewest this year.
"He loves the matchups when they come like that, if it does in this game," Seahawks coach Pete Carroll said. "We'll see how they want to play us and all. But he's got a great attitude about it. He knows that these are opportunities for him to get better, and he's challenged by the really good players that he goes against, and he loves that.
"He's developing a really wide range of skills that he can bring to our game, and against the guys we're going against, he's going to need every bit of it just to find some space. They're really good and tough, so it'll be a fun matchup to watch."