The New York Giants were not ready to board the Nick Mullens express.

After the San Francisco 49ers quarterback torched the Oakland Raiders in his first career start, New York handed him his first loss with a 27-23 victory on Monday at Levi's Stadium. The Giants snapped a five-game losing streak and improved to 2-7, while the 49ers fell to 2-8 in a contest that had more impact in the race for draft positioning than the playoff battle.

Eli Manning hit Sterling Shepard for the game-winning touchdown with less than a minute remaining and threw for 188 yards and three scores in the win, two of which went to Odell Beckham Jr. Saquon Barkley added 67 rushing yards and 33 receiving yards as well.

Mullens finished with 250 passing yards, one touchdown and two interceptions, while Matt Breida carried the offense for stretches with 101 rushing yards, 31 receiving yards and two total touchdowns. San Francisco had an opportunity to win on the game's final play, but Mullens' throw sailed out the back of the end zone.

Giants Are Biggest Threat to Saquon Barkley's Ceiling

The successful start of Barkley's career is all the more remarkable when taking his teammates into consideration.

Football Outsiders ranked New York's offensive line as the league's worst run-blocking unit through nine weeks, and the struggles were evident when there was a swarm of 49ers on him seemingly the moment he took a handoff. It is a testament to his individual brilliance he was able to shed tacklers and put up 100 total yards, 23 of which came on a critical catch that brought the Giants into the red zone on the winning drive.

He tallied 519 rushing yards, 497 receiving yards and seven total touchdowns through his first eight games and has flashed the talent to be a versatile difference-maker who can challenge for 1,200 rushing yards and 800 receiving yards a la Le'Veon Bell.

That is surely what the Giants envisioned when they opened themselves up for criticism by taking a running back with the No. 2 overall pick even with talented quarterbacks available and 37-year-old Manning's prime well in the rearview mirror.

Barkley has thrived and looks the part of a building block who can put up monster statistics in a well-designed offense with talented playmakers around him much like Todd Gurley does on the Los Angeles Rams. The question, though, is whether he will get the well-designed offense and capable blockers up front in time for his prime.

The Giants need a franchise quarterback to follow Manning who can take the pressure off Barkley's shoulders and prevent opposing defenses from stacking the box. They also need to take drastic steps along the offensive line lest they risk injury and stunted development for the Penn State product.

That means a team that has made the playoffs just twice in the last nine seasons—and is all but eliminated in 2018—is now tasked with putting the right pieces around a franchise running back to unlock his full potential all while addressing the defensive side of the ball as well.

The early returns are anything but promising with arguably the league's worst offensive line leading the way, and it is understandable if Giants fans are skeptical about the future.

New York's roster is more of a long-term impediment to Barkley than any on-field opponent.

Nick Mullens Shows 49ers Last Week's Stellar Performance Was an Anomaly

Mullens took the NFL world by storm with his debut performance in front of a national audience on Thursday Night Football in Week 9. He finished 16-of-22 for 262 yards, three touchdowns and zero interceptions in the win over the Raiders by dissecting the defense, comfortably stepping up in the pocket and exploiting openings downfield.

There wasn't nearly as much of that Monday.

Linebacker B.J. Goodson set up the Giants' first touchdown—a strike from Manning to Beckham—with an interception in the first half when San Francisco was pinned deep in its own territory. Mullens stared down Kendrick Bourne and attempted to force the ball into a tight window across his body and paid the price.

Mullens benefited from a dropped interception later in the game and airmailed a deep ball to Bourne on the first possession of the second half.

He struggled to throw outside the numbers and did so late multiple times, which is one of the riskiest plays a signal-caller can make since it gives defenders additional time to break on the ball. What's more, Goodson intercepted him again in the fourth quarter when the Southern Mississippi product threw behind Marquise Goodwin, which ended a promising drive.

In fairness to Mullens, he is not supposed to be starting Monday night football games in November. The 49ers traded for Jimmy Garoppolo last season to be the franchise quarterback for years, but he was lost for the season to a torn ACL. What's more, C.J. Beathard's wrist injury gave Mullens the opportunity to start against the Raiders in the first place.

He still managed 250 passing yards and has largely held his own as a third-stringer pressed into action, but some of the mistakes he made against the Giants are the ones NFL defenses will feast on long-term.

Mullens also hasn't exactly been working against the 1985 Chicago Bears' defense seeing how Football Outsiders' DVOA metrics place New York's defense 26th overall and 27th against the pass and the Raiders 31st overall and 32nd against the pass.

The bottom line is Mullens is not someone who is going to throw three touchdown passes on a weekly basis, even if he has made a name for himself.

What's Next?

The Giants host the Tampa Bay Buccaneers in Week 11, while the 49ers head into their bye.