The Denver Broncos have had a difficult season under rookie head coach Vic Fangio, but saw a beacon on light on Sunday with the debut of rookie quarterback Drew Lock.

But even in victory, Lock showed that he’s not quite caught up to the changes of playing in the NFL.

Lock, a second-round pick out of Missouri, started the season on injured reserve with a thumb injury. By the time he recovered, the Broncos had fallen well out of the playoff race and moved away from Week 1 starter Joe Flacco, who landed on injured reserve with a neck injury.

The Broncos gave a healthy Lock his shot on Sunday, and he prevailed with a steady effort in a 23-20 thriller over the Los Angeles Chargers.

So, how exactly does pass interference work?

The winning field goal by Brandon McManus was set up by a late pass interference call that advanced the ball 37 yards with nine seconds remaining. Lock’s deep pass to Courtland Sutton fell incomplete, but still got the Broncos into field-goal range.

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After the game, Lock told CBS that he was surprised by the result of the play.

New league, new rules

Pass interference in college is spot foul up to 15 yards, where the penalty is capped. In the NFL it’s simply a spot foul, a rule that Lock likely knew, but got a pleasant reminder of during his professional debut after four years of playing by college rules.

Lock finished his day completing 18-of-28 pass attempts for 134 yards with two touchdowns and one interception — far from an earth-shattering debut, but a solid one that resulted in a win.

For Broncos fans who watched Denver start 3-8 with quarterbacks not named Lock, it was more than good enough.

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