While it’s often a mistake to read too much into Week 1, the concern level in Denver about Peyton Manning has to be running high after the Broncos’ 19-13 win over the Ravens.

A sensational effort on defense (Baltimore was held to just 173 total yards and no offensive touchdowns) barely overshadowed yet another woeful outing by Manning, who looked just as bad Sunday as he did most of the final two months of last season.

And how bad was Manning last season? Bad enough to get booed off his own home field in a playoff loss to the Colts.

The 39-year-old Manning looked every bit his age against the Ravens, completing just 24 of 40 passes for 175 yards and no touchdowns while throwing an ugly pick-six interception. His final passer rating was a Geno Smith-esque 59.9.

Manning’s arm strength looks shot (no surprise, considering his four neck surgeries), and he looks even less mobile than usual — if that’s even possible. Baltimore sacked him four times Sunday.

As long as the Broncos’ defense continues to bring the lumber like it did against the Ravens, Denver will be a contender and perhaps still the favorite in the AFC West.

But if the Broncos keep winning, it likely won’t be because of Manning. No wonder Denver reportedly tried to trade Manning and then forced him to take a big pay cut in the offseason after he insisted on returning.