What the Denver defense demonstrated in the first half of its game last week against the San Francisco 49ers was a remarkable lack of discipline.

Its poor performance left Joe Woods, the Broncos’ defensive coordinator, disappointed in his unit.

“We weren’t ready to play,’’ Woods said.

By halftime, the Denver D had committed eight penalties, four in the 49ers’ 59-second, 72-yard, touchdown drive to end the half, a defensive debacle that turned a 13-0 deficit into a game-deciding 20-0 hole.

Pass rusher Von Miller jumped offsides three times.

There was poor coverage in the secondary, particularly against tight end George Kittle, who had a whopping 210 yards receiving by the intermission.

When the 49ers ran the ball to allow Kittle to catch his breath, they ran it effectively as Jeff Wilson Jr., an undrafted rookie who was part of the leadership council his senior year at North Texas, rushed for 53 yards.

“I was very disappointed in terms of how we played in the first half,’’ Woods said. “I talked to the guys and we addressed it on Tuesday.’’

At halftime, the 49ers were on pace for 40 points and 622 yards in total offense. The second half was much different. The Denver D held the 49ers to 79 yards and zero points after halftime – although when the Broncos absolutely needed a stop in the game’s final 4 minutes, they allowed quarterback Nick Mullens to convert back-to-back third down passes.

Woods was asked what he can do about getting his defenders’ mindset correct from the jump. To this, he passed the responsibility to the professional standards every player must carry.

“I’ll be honest with you—from a mindset standpoint, I can’t do anything,’’ he said. “I stress what we need to do to have success just from a game-plan standpoint and how we need to play.

“To me, from a player standpoint, it’s just their motivation and their self-motivation. If their mindset’s right and they’re ready to play early, that’s on them. I can’t get them going from that standpoint.”

I’m not sure other NFL coaches would agree with Woods on that. Coaching is about more than Xs and Os. Notre Dame does not beat Army, 12-6 in 1928 if not for Knute Rockne’s “Win one for the Gipper” speech.

But I understand the point Woods was trying to make – that motivation, by and large, comes from within, and not outside sources. As players from all four major sports have said in so many words over the years, if you need a speech to get motivated to play, you probably wouldn’t have what it takes to be playing in the first place.

After all, “The Gipper Speech” might have helped Notre Dame rally in the second half against Army, but the Fighting Irish did lose its next, and final two games to finish 5-4.