Missing two top players and their starting right tackle, the Washington Redskins put on their most prolific offensive performance of the season Sunday but fell short in their bid to upset the New England Patriots, losing, 34-27, before a FedEx Field crowd of 77,825.

Wide receiver Santana Moss could not control a Rex Grossman pass near the New England goal line and tipped it to Patriots linebacker Jerod Mayo to seal Washington’s fate with 22 seconds left.

With the loss, Washington fell to 4-9. After opening 3-1, the Redskins have lost eight of their last nine and are officially eliminated from the playoffs. The loss also ensured that Coach Mike Shanahan will have a losing record in consecutive 16-game campaigns for the first time in his 18 seasons as a head coach.

New England, meanwhile, improved to 10-3, tied for the best record in the AFC.

“Always disappointing when you can’t finish a game,” Shanahan said. “I thought we did a number of good things today, but the end of the day, we fell short. Some guys stepped up and really did a great job of playing at a high level even though they didn’t get a lot of reps during the week.”

Grossman and Co. engaged Tom Brady and the Patriots in a shootout that almost ended in an upset, although the odds were stacked against Washington. The Redskins were missing their leading pass-catcher, tight end Fred Davis, and franchise left tackle Trent Williams, who were suspended last week for the remainder of the season for violating the league’s substance abuse policy. Right tackle Jammal Brown went down during warmups with a groin injury.

But, taking advantage of New England’s 32nd-ranked defense, the Redskins generated a season high in both points and yards (463). Grossman completed 19 of 32 passes for 252 yards and two touchdowns, and rookie running back Roy Helu rushed for 126 yards on 27 carries.

Brady completed 22 of 37 passes for 357 yards, three touchdowns and an interception, and tight end Rob Gronkowski recorded six catches for 160 yards and two touchdowns to lead New England.

In a game considered a mismatch going in, the Redskins’ offense found itself in position to tie or win the game after cornerback Josh Wilson intercepted Brady in the back of the end zone on a play that would have put New England up by two touchdowns with 6 minutes 37 seconds left.

Grossman then completed two passes for 36 yards (13 to Donte Stallworth and 23 to Jabar Gaffney), but the Redskins largely stayed with the run as they drove downfield. Helu ran five times for 19 difficult yards, and fellow rookie Evan Royster had two carries for 20 yards as Washington moved into scoring position.

Facing second and goal from the 5, Grossman completed a pass to Moss in the end zone, but the play was overturned by officials who called Moss for offensive pass interference, saying he pushed off Patriots defensive back Julian Edelman.

Two plays later, facing third and goal from the 9, Grossman threw to Moss over the middle, but the wide receiver bobbled the catch and tipped it into the hands of Mayo, who made a diving catch at the 7 to quash Washington’s upset hopes.

“I didn’t make the play,” said Moss, who strongly disagreed with the pass interference call. “Plain sight. Didn’t make the play. But that’s football.”

Early on, it appeared the Redskins would miss Williams badly. With Washington pinned deep in its territory and facing third and nine from the 5, former Redskins defensive end Andre Carter blew past left tackle Willie Smith and hit Grossman hard, forcing a fumble in the end zone. New England defensive tackle Vince Wilfork recovered the ball for the touchdown.

On the next possession, Washington threatened to score a touchdown, but ended up settling for a field goal. Grossman completed a 51-yard bomb to Stallworth — the Redskins’ longest completion of the season — to the New England 14-yard line on that drive.

After a nine-yard completion to Stallworth three plays later, Grossman moved the Redskins to the 2-yard line, but a false start on tight end Logan Paulsen backed up Washington, and the Redskins had to settle for a 24-yard Graham Gano field goal.

The Patriots’ offense struck quickly following Gano’s kickoff (which went out of bounds and set up New England at its 40), using a two-play, 60-yard scoring drive to score.

Brady completed a short pass to a diving Gronkowski at the 50, who got off the ground and started to run downfield. Safeties Reed Doughty and DeJon Gomes tried to wrestle the 6-foot-6, 265-pound tight end to the ground, but he broke the tackles and rumbled all the way to the Redskins 11-yard line. Washington challenged the play to see if he had stepped out of bounds, but lost. On the next play, Brady completed a touchdown pass to Gronkowski, and New England went up, 14-3.

“He’s a big guy, but I can’t really make an excuse,” said Gomes, who started at free safety in place of hobbled veteran Oshiomogho Atogwe. “We should’ve had him down, especially because it was both of us, and it was my man, so I should’ve made a tackle, and I should’ve put a hand on him so he couldn’t have gotten up.”

The Redskins’ offense fired back, however, putting together an eight-play, 84-yard drive capped by a nine-yard touchdown pass from Grossman to Gaffney.

Washington trailed 14-10 heading into the second quarter, when offensive coordinator Kyle Shanahan pulled a trick out of his bag.

On the first play of the quarter, Grossman lined up in the shotgun and handed off to Helu, who swept to his right but pitched the ball to wide receiver Brandon Banks on a reverse. Banks darted to the edge and then heaved it left-handed downfield to an open Moss, who caught the ball at the 16-yard line and ran into the end zone untouched for a 49-yard score.

The play was the longest pass by a non-quarterback in Redskins history, and gave Washington a 17-14 lead following Gano’s kick. The half ended with the score tied at 20 thanks to a pair of field goals from the Patriots and one from the Redskins.

Brady hooked up with Gronkowski on another touchdown — a 37-yard catch-and-run — early in the third quarter, and Grossman answered with a six-yard touchdown pass to backup wideout David Anderson.

But Brady — as he has so often during his storied career — proved the hero, connecting with an open Wes Welker on a slant route for a 24-yard touchdown with 4:26 left in the third for the deciding score.

Full Redskins coverage:

Summary: Patriots 34, Redskins 27

Photos: Scenes from FedEx Field

Live Q&A, Monday at 11 a.m.: Thomas Boswell

Live Q&A: Monday at 12:30 p.m.: NFC East Trash Talk

Photos: Top 10 moments from NFL Week 14

Boswell: Helu proves his worth

Reid: Success gives way to failure

Moss vents after the game

Mistakes, flags cost the Redskins

Chad: An action against Snyder

Bog: Redskins-Patriots best and worst

Postgame Q&A with Cindy Boren

The Insider: Latest updates

Redskins schedule and results