Momentum can change fast on a Sunday afternoon in the National Football League. The San Francisco 49ers were reminded of that in a Week 4 home game against the Dallas Cowboys.

After getting out to a 14-0 lead in the first quarter, the visiting Cowboys outscored the 49ers 24-3 in the next 45 minutes of the game.

San Francisco is now 1-3 on the year. Dallas improved to 3-1.

Here's what we learned from the game.

Deep Ball, Fourth-down Pass Prove to Be Costly

Blaine Gabbert's longest pass attempt of the game was intercepted at a key juncture of the afternoon. Gabbert's deep ball for Torrey Smith was intercepted by Morris Claiborne and returned 27 yards down the left sideline when the 49ers were trailing by four points in the fourth quarter.

Dallas came up with the game's first turnover. It was a timely one.

Trailing by seven points with 4:11 left to play, San Francisco's offense was still in position to tie the game. Smith was targeted again by Gabbert on a 4th-and-6 from Dallas' 35-yard line with 1:49 left in the fourth. The rollout throw to Smith was three yards shy of the first-down marker. Claiborne knocked Smith out of bounds and the 49ers turned the ball over on downs.

Both throws to Smith represented critical moments in the loss. Gabbert completed 16-of-23 pass attempts for 196 yards with one touchdown, one interception and finished with a quarterback rating of 91.9.

The 49ers got on the board in the first quarter with a 33-yard Gabbert pass to Jeremy Kerley who was wide open on a deep crossing route. The veteran wideout made Cowboys safety Barry Church miss just shy of the goal line with a nifty cut-back into the end zone. Pierre Garçon added a 3-yard rushing touchdown to give the home team a two-touchdown lead.

Kerley led the 49ers with six catches for 88 yards on nine targets. Smith's lone reception of the game came on the fourth-down stop.

Chip Kelly said he thought Gabbert played a good game. The lone blemish was the deep ball thrown to Smith. The coach said he would review the tape to further evaluate his play. Kelly said there's no talk of changing quarterbacks after a third-straight loss.Bowman Injured on Non-contact Play; Buckner Hurt in Fourth Quarter

San Francisco's All-Pro linebacker was injured on a non-contact play in the third quarter. NaVorro Bowman was able to get up and walk off the field, but he was later carted to the locker room as the Cowboys were driving, trailing 17-14 late in the quarter.

Nick Bellore replaced Bowman at inside linebacker.

Ezekiel Elliott put the Cowboys ahead for good with a 1-yard touchdown plunge to make it a 21-17 game with 1:08 left in the third. The rookie runner finished the game with 138 rushing yards on 23 carries.

Bowman was ruled out for the remainder of the game with a lower-leg injury. He finished the day with eight tackles and one sack.

First-round draft pick DeForest Buckner was also carted off the field. The No. 7 overall pick appeared to suffer a lower-body injury when the Cowboys were running the clock out with less than two minutes to play.

Kelly said he had no injury updates on either player in his post-game remarks.

49ers Make Early Strides on Third Down

Gabbert was 7-of-9 passing for 109 yards and had one touchdown in the first quarter. He threw for 119 yards in last week's loss to the Seattle Seahawks.

San Francisco also struggled with third-down conversions in Week 3. Against the Cowboys, the 49ers began the game 7-of-7 on third downs. They finished the day 8-of-14.

The sixth third-down conversion was a 3-yard Hyde touchdown run behind an amazing block by right tackle Trent Brown.  It was Hyde's NFL-leading fifth rushing score of the year and his first time with rushing touchdowns in back-to-back games.

The early momentum on third down was a positive development for the 49ers. The coaches will have to evaluate third-down execution in the second half going into a Week 5 home game against the Arizona Cardinals on "Thursday Night Football." Third-quarter Scoring Draught Ends

A 32-yard Hyde run in the third quarter set up a 36-yard Phil Dawson field goal. It was San Francisco's first third-quarter points of the season and the team's only second-half points on Sunday.

Hyde finished the game with 15 carries for 74 yards. The 49ers have scored three points in the third quarter this season. This will have to change going into Week 5 and beyond.

Robinson Starts at Right Cornerback 

Rashard Robinson started for Jimmie Ward and made his first tackle on first play of the game. Eric Reid lined up in the nickel defensive back position, which meant Jaquiski Tartt played deep at safety next to Antoine Bethea.

Reid later dropped an interception, but the Cowboys were unable to score on their opening drive after Dan Bailey missed a 47-yard field goal wide left.

Robinson later recorded a key pass breakup on a third-down Dak Prescott pass intended for Cowboys wideout Brice Butler.

Robinson was shaken up on a 23-yard Elliott run in the third quarter. He returned, however, and broke up a key 3rd-and-goal pass from Elliott to Butler in the end zone.

Robinson finished the game with five tackles and three pass breakups in his first NFL start. The fourth-round draft pick's development is a good sign for the 49ers defense if Ward will be out for the Cardinals game. Niner Nuggets

-- Aaron Burbridge made his first career start when San Francisco opened in a four-wide receiver set. The sixth-round draft pick later caught his first NFL pass for a gain of 5.

-- Bowman recorded San Francisco's first sack of the game on Prescott. The critical third-down stop forced Dallas' first punt of the game.

-- Michael Wilhoite replaced Gerald Hodges as the weak-side inside linebacker in San Francisco's base-down defense. Wilhoite tied Bethea with 12 tackles for the team lead.

-- Ronald Blair III and Chris Davis split a second-quarter sack on Prescott. It appeared like it would be a key stop on third down, but a questionable penalty on Jaquiski Tartt for a late-hit extended Dallas' drive. Prescott put Dallas on the board with a 20-yard touchdown pass to Terrance Williams. Dallas' momentum began to roll from there.