ST. LOUIS — In its first game after their bombshell trade of wide receiver Percy Harvin to the New York Jets Friday, the Seattle Seahawks continued their unsuccessful search for answers.

Falling behind 21-3 midway through the second quarter, the defending Super Bowl champions slipped to 3-3 with a 28-26 loss to the St. Louis Rams on Sunday at the Edward Jones Dome.

Seattle drew within 21-19 when quarterback Russell Wilson hit tight end Cooper Helfet with a 19-yard touchdown pass with 9:44 remaining in the game.

But the Rams (2-4) promptly drove 80 yards for the eventual winning touchdown when quarterback Austin Davis found tight end Lance Kendricks for a 4-yard scoring strike at the 5:36 mark. Davis completed 18 of 21 passes for 152 yards and two touchdowns.

Wilson, who had 313 yards on 23-of-36 passing and ran for 106 yards, connected with wide receiver Doug Baldwin on a 9-yard touchdown pass with 3:18 left.

However, St. Louis melted away the remaining time, keeping the ball on a fake punt when punter Johnny Hekker completed an 18-yard pass to running back Benny Cunningham on fourth-and-3 at the Rams 18. Running back Tre Mason then ran for 9 yards on a third-and-1 play for the first down that ended the Seahawks’ hopes of a comeback win.

After Seattle placekicker Steven Hauschka initiated scoring with a 24-yard field goal at the 9:01 mark of the first quarter, St. Louis scored the next 21 points.

Cunningham returned a kickoff 75 yards to set up a 31-yard field and the Rams cashed in as Mason powered 6 yards up the middle for his first NFL touchdown with 5:19 left in the quarter.

Cunningham made it 14-3 with 13:12 remaining in the half when he scored on a 5-yard shovel pass from Davis, capping a nine-play, 74-yard drive. The Seahawks chipped in three first downs on penalties, including a face mask on cornerback Tharold Simon that wiped out a third and goal at the 25.

Wide receiver Stedman Bailey returned a punt 90 yards with 7:05 left in the half as Seattle fell for a fake from wide receiver Tavon Austin on the other side of the field. That left Bailey with just two defenders to elude on the right side.

Hauschka converted a 35-yard field goal with seven seconds remaining in the half, cutting St. Louis’ halftime advantage to 21-6.

NOTES: Four Seattle starters — CB Byron Maxwell (calf), LB Bobby Wagner (foot), C Max Unger (foot) and TE Luke Willson (groin) — were inactive. Backup TE Zach Miller (ankle) also sat out and starting FB Derrick Coleman (foot) didn’t play after getting injured in pregame warmups. … St. Louis reactivated WR Chris Givens after a two-week absence, but deactivated WR Austin Pettis, who was listed as probable with an ankle injury. … When the Rams’ Rodger Saffold started Monday night at right guard, it marked the fourth different O-line position that he opened a game at in the last two years.