Lock's late scoring drive powers Seahawks to stunning win over Eagles
The Seahawks snapped their four-game NFL losing streak, improving to 7-7 to keep their post-season hopes alive.
The Eagles, already play-off bound, lost their third straight and fell into a tie with the Dallas Cowboys for first place in the NFC East division.
The Seahawks had not led all night when they took over on their own eight-yard line with less than two minutes remaining.
Lock marched them up the field, completing five of 10 passes on the drive. That included the game-winner to rookie Smith-Njigba, who used a nifty move to elude veteran cornerback James Bradberry and reached out to haul in the ball.
"'Amazing' won't do it justice but amazing," an emotional Lock told broadcaster ESPN of the winning drive, heaping praise on his teammates.
"It takes a special group to rally around the guy that, you know, has come into his second game of the year, right? Used to the same thing all year long. Same cadence, same spin of the ball, everything.
"For a team like that, not just the offence but the defence to rally around me tonight, that was amazing," he said.
With quarterback Geno Smith in questionable shape with a groin injury, Lock did not know for sure if he would be playing until shortly before the game.
Smith was listed as "available" but Lock got the nod and completed 22 of 33 passes for 208 yards and a touchdown.
DK Metcalf made five catches - three of them on the final drive - for 78 yards and Ken Walker had 86 yards and a touchdown on 19 carries.
The Eagles had a last opportunity, but Julian Love made his second interception of the fourth quarter, picking off ailing Philadelphia quarterback Jalen Hurts's pass intended for A.J. Brown to seal the win.
The Eagles, with Hurts playing despite "flu-like symptoms," opened the game with a touchdown drive capped by the quarterback's three-yard scoring run.
They led 10-3 at half-time after field goals from Philadelphia's Jake Elliott and Seattle's Myers.
Seattle knotted it at 10-10 on Kenneth Walker's 23-yard touchdown run early in the third quarter.
Philadelphia responded with a one-yard touchdown run from Hurts before Elliott drilled a 45-yard field goal to pull Seattle to 17-13.
Hurts, whose 14 rushing touchdowns this season have tied Cam Newton for the most by a quarterback in a single season, also threw two interceptions.
The result left the 11-3 San Francisco 49ers in front in the race to claim the top seed in the NFC and a first-round playoff bye.
It also meant the Detroit Lions, at 10-4 atop the NFC North, have not yet clinched a play-off berth.
If the Lions win their final three regular-season games they could still capture the second seed in the conference.