Jared Goff threw a perfect game on Monday night.

The Detroit Lions quarterback completed 18 of 18 passes for 292 yards and two touchdowns during a 42-29 win over the Seattle Seahawks at Ford Field.

Still, the Rams’ former No. 1 overall draft pick didn’t finish with a perfect passer rating.

“Didn’t I?” Goff said when informed of the statistical anomaly during his post-game press conference. ‘Yes, I don’t know. That system is strange.’

Against the Seahawks, Goff set the NFL record for most passes in a game without an incompletion, surpassing Kurt Warner’s 10-for-10 performance for the Arizona Cardinals in 2005. However, Goff’s overall stats for the evening were only enough for a 155.8. passer rating at a possible 158.3.

Last month, Arizona Cardinals quarterback Kyler Murray became the latest quarterback to achieve a perfect passer rating against the Rams, completing 17 of 21 passes for 266 yards and three touchdowns with no interceptions.

Read more: Explaining the mystery behind the revival of Sam Darnold, Derek Carr and Baker Mayfield

So there is clearly more to the assessment of the graduate than just the completion percentage.

Goff was sacked three times by Seattle, including once for a safety late in the game. Also in the fourth quarter, Goff had an incomplete pass cleared by an offensive pass interference call on teammate Brock Wright.

But none of that plays a role in a quarterback’s passer rating.

The statistic that kept Goff from receiving a perfect rating was the percentage of touchdown passes per pass attempt. The minimum for passer rating perfection is 11.9%, and Goff fell a bit short at 11.1%. Oddly enough, he would have actually gotten a perfect rating if he had attempted two fewer attempts.

Speaking of quirks, the Lions posted a perfect passer rating as a team, and Goff played a key role in the play that put them over the top. Midway through the third quarter, Goff caught an eight-yard touchdown pass – the first touchdown reception of his career – from receiver Amon-Ra St. Brown.

Read more: Hernández: Have you heard this before? Injuries keep Chargers Justin Herbert from flourishing

So yeah, it was a pretty incredible game for Goff, who was somehow overlooked when coach Dan Campbell was handing out game balls. The coach instead gave them to receiver Jameson Williams, safety Kerby Joseph and offensive coordinator Ben Johnson before sheepishly admitting to reporters that he hadn’t realized Goff had completed all his passes.

“I just gave the game ball to someone else, so I feel terrible right now,” Campbell said when informed of Goff’s stats. “I knew he played a great game. I didn’t know he was perfect. I didn’t know he was literally 18 for 18, but I knew he played really well. You could feel it.”

Telling reporters of Campbell’s regret for not giving him a game ball on such a special night, Goff laughed.

“That’s okay,” he said. “I’m just happy we won.”

Get the day’s best, most interesting and strangest stories from the LA sports scene and beyond with our newsletter The Sports Report.

This story originally appeared in the Los Angeles Times.