Puka Nacua’s incredible start to his NFL career hit a historic high Sunday afternoon.

But perhaps more importantly, he finally found the end zone when it mattered most for the Los Angeles Rams.

Nacua caught a 22-yard walk-off touchdown to secure a 29-23 overtime win over the Indianapolis Colts for what was his first career score. Nacua was wide open deep in the middle of the field at Lucas Oil Stadium, and he split a pair of Colts defenders to fight his way into the end zone and end the game.

The touchdown extinguished the Colts’ rally, with Indianapolis having climbed back into the game from 23-0 down with a pair of fourth-quarter touchdowns to force overtime.

Nacua finished with nine catches and a career-high 163 receiving yards in the win. That brought him to 501 receiving yards this season, which is the second-highest among all wide receivers in the league. Only Minnesota Vikings star Justin Jefferson — who had 85 yards and two touchdowns in a win over the Carolina Panthers on Sunday — has more.

Nacua has 39 receptions through his first four games this season, and he now has three games with at least 100 receiving yards. He’s the first player in NFL history to hit those two marks, and record 501 receiving yards, in the first four games of his career.

The Rams selected Nacua in the fifth round of the NFL Draft earlier this year out of BYU. With normal starter Cooper Kupp beginning the season on injured reserve, Nacua was thrust into the starting lineup right away.

He had 119 receiving yards on 10 catches in their season-opening win against the Seattle Seahawks, then had 147 yards on 15 catches in Week 2. While it was still an impressive outing, Nacua’s worst showing came with his 72 receiving yards in last week’s loss to the Cincinnati Bengals.

Matthew Stafford went 27-of-40 for 319 yards with a touchdown and an interception in the win Sunday. He’s thrown for at least 260 yards in the first four games this season, too. Running back Kyren Williams had 103 yards on the ground and two touchdowns on 25 carries. The Rams, now 2-2 on the season, host the Philadelphia Eagles next week.

While Kupp is expected to return from injured reserve in the near future after his hamstring injury, Nacua isn’t likely to go anywhere. He’s here to stay, and a healthy Kupp paired with Nacua could undoubtedly lift the Rams’ offense to another level as they reach the middle stretch of the season.