INDIANAPOLIS – It was the shootout Jim Irsay had predicted going into Week One.

And in the end, the Colts had a chance to escape Lucas Oil Stadium with a victory that looked bleak in Sunday's first half.

Ultimately though, it was how the Colts played the first quarter and a half that cost them in their 2016 season opener.

The fast start Irsay and Chuck Pagano had wanted in 2016 was absent on Sunday.

An 18-point first-half deficit was eventually erased, but not completely, as Detroit kicker Matt Prater connected from 43 yards out with four seconds remaining to give the Lions a 39-35 victory over the Colts.

The comeback was valiant, and nearly epic, but it was what transpired in the first 28 minutes that cost the Colts in the end

"This has happened too many times," Chuck Pagano said after Sunday's opener, "and I know this team knows how to finish (but) we have to figure out how to start."

With the Colts severely banged up in the secondary, and with CB-Patrick Robinson and S-T.J. Green exiting in the first half, too, the expectation was Detroit would pepper Indy through the air.

They did that early and often on Sunday.

Three of Detroit's first four drives covered at least 75 yards, and all three ended in the end zone.

With the Colts having to punt on each of their first three drives, the scoreboard read 21-3, in favor of the visitors, just before intermission.

Things began to sway to the home team early in the second half.

Andrew Luck was a major reason why. Luck was nothing short of spectacular in his 2016 debut.

Spearheading a second-half comeback that was unfolding much like what fans have grown accustomed to from Luck, the quarterback showed no signs of right shoulder issues.

Luck was 31-of-47 for 385 yards, three touchdowns and no interceptions, playing in his first regular season game since last November.

With the fourth quarter clocking ticking late on Sunday and the Colts down six, it was Luck conducting a 94-yard drive, with a perfect 6-of-6 series, giving the Colts a 35-34 lead with 37 seconds remaining.

Needing one final stop, the defense could not finish off a vintage Luck comeback.

"We knew it was going to come down to us," inside linebacker D'Qwell Jackson said of the defense having a chance to seal a victory before Matt Prater's 43-yard game-winning field goal.

"The game plan was simple. We have to defend 25 yards. We knew what we were up against and we didn't make plays."

Following the game, the message was clear on what had to improve in Jackson's unit---tackling.

"Missed tackles," Robert Mathis said of what unglued the defense on Sunday.

"Defense 101. Have to make those tackles. When you do things like that, you breathe life into offenses. We've got to do a better job of getting the guys on the ground."

Going into Week Two at Denver, the Colts will have their secondary tested again given the growing list of injuries for that unit.

Playing in one of the NFL's most hostile environments, against arguably the league's most disruptive defense, a fast start will certainly not be handed to the Colts.

But if the Colts want to avoid a third straight 0-2 start, they must get out of the gates quicker.

"That is a great question," Pagano said on Sunday of where the slow starts are attributed to. "Obviously, we haven't solved the problem yet.

"We are more than capable. (When) you can come out and move the ball like we moved it towards the end of the first half and then move it in the second half and get off the field...(but) it has to be better.

"This is going to be a tough one to get over, but we've got to go on the road and play a really good (Denver) football team out west next week and they're not going to feel sorry for us."