SEATTLE --A pair of momentum-swinging, end zone-to-end zone touchdowns were too much for the Broncos to overcome in Seattle.

Jermaine Kearse returned a kickoff 107 yards for a touchdown and Brandon Browner scooped up a fumble in his own end zone and raced 106 yards for a score, helping the Seahawks defeat the Broncos 40-10 in Saturday night's preseason matchup at CenturyLink Field. 

The Seahawks took advantage of Denver's mistakes, turning four Broncos turnovers into 17 points.

"When you are minus four, you're going to win 10 percent of your games. When you're playing a good team, you're going to win zero percent," Broncos Head Coach John Fox said after the game. "So we've got that to look at, ball security being something that we'll continue to work."

Seattle jumped out to a 33-7 halftime lead despite a strong performance from Broncos quarterback Peyton Manning, who completed 11 of 16 passes for 163 yards and a touchdown to wide receiver Wes Welker – Welker's first in a Broncos uniform.

But after the game, Manning's attention was turned to the kinks the Broncos will have to work out in the coming weeks.    

"I think our team needs to improve and needs to use this week to get better," Manning said. "We have a long way to go."

"We had a lot of things that we need to fix and correct," he added. "I do think there are things that are correctable, but we have to do it."

While the first half was marked by an outpouring of big plays from both teams, several of Seattle's culminated in the end zone – including Browner's return of Broncos running back Ronnie Hillman's fumble, which turned a 14-point momentum swing in favor of the Seahawks. 

"It definitely weighs the heaviest in a game like this," Manning said. "Any time that leads to points – two 14-point swings on a kick return and fumble recovery that took a total of 20 seconds – those are game-changing plays. They are hard to overcome. We'll learn from it. Those are correctable mistakes."  

Ultimately, those setbacks took the steam out of a Broncos offense that rolled up 209 first-half yards and held a halftime advantage of over seven minutes in time of possession.

"It felt like we were beating ourselves," wide receiver Demaryius Thomas said. "It was putting ourselves in a bad situation, especially when they go down and score on us."

The Broncos had to play from behind throughout the game after spotting Seattle an early lead.       

Seahawks quarterback Russell Wilson put Seattle up 7-0 with 8:41 left in the first quarter after he picked up a fumbled snap, rolled out of the pocket and fired a strike to Jermaine Kearse in the end zone for a 12-yard touchdown pass.

The score capped a 10-play, 65-yard drive for Seattle.

On the ensuing drive, the Seahawks picked up more steam after turning a big play for the Broncos into a big play of their own – a theme that would resurface throughout the game.

Manning found tight end Julius Thomas on a 20-yard strike into Seahawks territory, but Thomas was stripped by Browner and Seattle recovered the fumble. The turnover set up another score, as Wilson led the Seattle offense on a five play, 30-yard drive culminating in a Steven Hauschka 42-yard field goal to extend the Seahawks' lead to 10-0.

The Broncos answered promptly with a nine-play, 80-yard drive – including a 31-yard pass from Manning to Thomas on third down – that culminated at the Seahawks 11-yard line with Manning passing to Welker, who dove into the end zone for his first score as a Bronco.

"Absolutely," Welker replied on whether it felt good to score for the first time in a Broncos uniform. "Any time you can get a few plays in and get a few catches, kind of get moving around and in a groove, in the feel of the offense and things like that, it's a good deal."

Welker's touchdown cut the lead to 10-7, but that score stood for only a matter of seconds.

Kearse took Matt Prater's ensuing kickoff seven-yards deep in the end zone and raced past the Broncos coverage team for a touchdown, extending the Seahawks' lead back to 10 in the blink of an eye.

Manning was again poised in his response, answering with another lengthy drive – including passes of 23 and 13 yards to Demaryius Thomas – that moved the Broncos within striking distance.

But on second-and-goal from the Seahawks 1-yard line, the ball squirted free from Hillman as he attempted to plunge into the end zone, setting up Browner's touchdown and effectively taking the wind out of the Broncos' sails.

"It gets a little frustrating not to score," Hillman said. "I think we did a couple of good things, but we had a lot of bad things. That's what (the preseason is) for, just to get all the bad things out of the way and just come back next week and continue to build on what we've done."   

Fox noted that the offense's ability to move the ball was one positive takeaway from the game.

 "I think we moved the ball well offensively," Fox said. "I think we had a moment but we had too many turnovers, we had a 14-point swing which makes it tough."

Even in a preseason game, the loss was an eye-opening experience for the Broncos to learn from according to wide receiver Eric Decker.