INDIANAPOLIS — The Indianapolis Colts fell to 1-2 on the season Sunday with a 20-16 loss to the Philadelphia Eagles at Lincoln Financial Field.

The Colts' defense overcame a shaky start to limit a talented Eagles (2-1) offense, but ultimately, an inability for the Indy offense to capitalize in the red zone — the Colts scored touchdowns on just 1-of-5 trips inside the Philadelphia 20-yard line — as well as some other key deficiencies led to a narrow road loss to the defending Super Bowl champions.

"Tough loss. The guys played hard," Colts head coach Frank Reich said. "We have to learn from this and learn from our mistakes. Obviously we did not take advantage of some opportunities. The biggest one of that in the offense is in the red zone. The defense did a good job for us with some turnovers, so we'll learn from this and get better."

Here are the FIVE THINGS LEARNED from Sunday's game against the Eagles:

• TOUGH START, FINISH: The Colts' offense couldn't get anything going to start Sunday's game, while the Eagles came out on fire. Inspired by the return of quarterback Carson Wentz — making his 2018 debut after suffering a torn ACL last December — Philadelphia went right down the field on its opening possession, going 79 yards in 12 plays and getting into the end zone with a 13-yard touchdown pass from Wentz to rookie tight end Dallas Goedert. The Indy defense would mostly put the clamps down from there, and then the Colts' offense had a chance to escape with a victory late, putting together a drive late in the fourth quarter that found Indy just four yards from a potential game-winning touchdown. But a sack of quarterback Andrew Luck on 4th and 3 by Eagles defensive end Derek Barnett officially sealed the game for the home team.

• LEONARD, AGAIN: Darius Leonard had a performance of historic proportions last week in a win over the Washington Redskins, as the linebacker finished with 19 total tackles — 15 of which were solo stops — and added a sack, a forced fumble and a pass defensed. For his efforts, Leonard was named the AFC's Defensive Player of the Week and voted by fans as the NFL's Rookie of the Week. How would Leonard respond on Sunday? Another top-notch performance: a game-best 13 tackles (nine solo stops and five total tackles for loss) with another two sacks and one pass breakup. Leonard, the league leader in tackles with 41, is tied for the most stops through the first three games of a season in NFL history; he trails only Ray Lewis (44) and London Fletcher and Zach Thomas (43 each). And, again — Leonard's just a rookie.

• OFFENSIVE STRUGGLES: Other than a couple drives, the Colts' offense couldn't get much going against one of the top overall defenses in the league. Indianapolis totaled just 209 net yards on the afternoon, including just 164 through the air and 68 on the ground — 33 of which were collected on one run by quarterback Andrew Luck. Luck, for a third straight game, spread the ball around — connecting with nine targets on the afternoon — but just couldn't connect at pivotal times throughout the ballgame. Also, after leading the NFL in third-down percentage the first couple weeks of the season, the Colts really struggled in that area on Sunday, converting just 2-of-12 (17 percent) of their opportunities. And, perhaps one of the most telling stats on Sunday: the Eagles had the ball for 40 minutes and 20 seconds; the Colts had the ball for 19 minutes and 40 seconds. "It is tough when you are fighting the clock a bit and don't feel like you are out there, especially in that first half, to establish a rhythm of any sort," Luck said. "We had our chances and we didn't take advantage of them as an offense and every play counts in this league."

• ALL-TIME RECORD: With his third field goal on Sunday, Colts kicker Adam Vinatieri tied the great Morten Andersen (565) for the most made field goals in NFL history. The record-tying kick was a 28-yarder with 14:20 left in the fourth quarter, which put Indianapolis ahead, 16-13. The next kick will really be historic for Vinatieri, who has one more Andersen all-time mark to break this season: the NFL's scoring record (2,544). Vinny now needs 34 points to top that list, too.

• NOTES OF INTEREST:

— With his five-yard touchdown pass to wide receiver Ryan Grant in the first quarter Sunday, Luck has now thrown at least one touchdown in 26 consecutive games, the longest active streak in the NFL.

— Luck's 33-yard run on Sunday tied a career-best set back in 2016.

— Through three games, Grant has 124 receiving yards on 13 receptions and one touchdown, the best start to a season in his career.

— T.Y. Hilton's fifth catch of the game sent him over 7,000 career receiving yards. He is just the fourth Colt to reach that plateau. He is also the fifth receiver since 2012 to have 7,000 yards receiving.

— Margus Hunt registered his first forced fumble and first fumble recovery of his career on a sack in the third quarter. Hunt finished the game with four tackles, 1.0 sack, 3.0 tackles for loss, one forced fumble and one fumble recovery.