SANTA CLARA -- The 49ers head into the bye week after taking another gut punch to the stomach.

The 49ers coughed up a late lead, as Eli Manning rallied the New York Giants to a 27-23 win Monday night at Levi’s Stadium.

Manning hit Sterling Shepard for a 3-yard touchdown pass with 53 seconds remaining for the winning points. The 49ers now have lost four games this season by four points or fewer, and fell to 2-8 on the season. The Giants improved to 2-7.

Here are three quick takeaways from the 49ers’ loss:

Mullens not as sharp in his second start

49ers coach Kyle Shanahan didn't make any promises for Mullens starting beyond this game. And the quarterback's second start wasn't as spotless as his Week 9 debut.

Mullens threw three touchdown passes without an interception in that 49ers win over the Raiders. He threw a pick in the first quarter of this game, though, as Giants linebacker B.J. Goodson intercepted a pass intended for Kendrick Bourne.

Three plays later, Eli Manning threw a 10-yard TD pass to Odell Beckham Jr., who found a space equal distance from 49ers defensive backs K’Waun Williams, Ahkello Witherspoon and Jimmie Ward.

Mullens led a drive for a field goal at the end of the first half, and he later threw an 11-yard TD pass to Matt Breida to cap the first series of the second half. The scoring pass gave the 49ers a 20-10 lead.

Mullens finished 27-of-39 passing for 250 yards and one touchdown with two interceptions. His last-second throw from the Giants' 21-yard line sailed out the back of the end zone as time expired, ending any chance of a 49ers comeback win.

 

Tight end George Kittle was the 49ers’ top pass-catcher with a career-best nine receptions for 83 yards. Breida rushed for 101 yards and one touchdown on 17 carries.

Defense puts clamps on Barkley

The 49ers managed to keep Giants rookie running back Saquon Barkley under control for most of the night. The No. 2 overall pick in the draft had an 18-yard run early in the game, but the rest of his yards didn't come easy, as the rookie finished with 67 on 20 carries.

Barkley did break free out of the backfield for a 23-yard reception late in the fourth quarter, setting up Manning’s winning pass to Shepard.

The 49ers’ pass defense wasn't as dominant as in last week's win over the Raiders, but Manning didn't put up gaudy numbers, either. He completed 19 of 31 passes for 188 yards and three touchdowns. Beckham caught four passes on 11 targets for 73 yards and two TDs.

The 49ers' pass rush had its best showing of the season one week earlier, racking up eight sacks against Derek Carr and the Raiders. Manning had been sacked 31 times in the Giants' first eight games, but the 49ers only got to him once, as DeForest Buckner and Dekoda Watson teamed up to bring him down for an 8-yard loss on a key third-and-7 play.

The 49ers took over and put together a go-ahead drive, as Robbie Gould made a 30-yard field goal with 2:50 remaining for a 23-20 lead.

Air quality unhealthy but doesn't affect play

There was a noticeable layer of haze Monday at Levi’s Stadium, but the smoke didn't appear to have any discernable impact on the game. 

According to the NFL, a game would be postponed or moved if the air-quality index was consistently above 200 for a significant period of time. This game was played with an index in the mid-160s, which is classified as “unhealthy.”

The poor air quality is a result of smoke from the Camp Fire, which has decimated most of the Northern California town of Paradise -- approximately 200 miles northeast of Santa Clara.

The 49ers hosted the Paradise High School football team, coaches and cheerleaders Monday. John Lynch, the 49ers' general manager, greeted the team before the game and invited them out to the field for the playing of the national anthem.