LAS VEGAS – The Giants entered their game Sunday against the Las Vegas Raiders confident they could earn a victory that would catalyze a turnaround in the second half of the season. Their optimism was due largely to the return of quarterback Daniel Jones, who started after missing the previous three games with a neck injury.

The good feelings lasted 21 offensive plays. That's when Jones – on the first play of the second quarter – suffered a knee injury that forced him from the game and could keep him out longer, depending on the results of the examinations and scans he will undergo Monday.

"He will get tested and find out where it's at," coach Brian Daboll said. "They gave him X-rays and came back nothing was wrong on the X-rays. We will get more tests, MRIs and stuff done tomorrow. … You never know with those things, so when we get back, we will get the information and see where it's at."

Without Jones for most of the game, the Giants lost to the Raiders, 30-6, and fell to 2-7 on the season.

How tough was it for Daboll to see Jones go down?

"Tough," he said. "You never want your guys to go down. He has worked really hard to get back and it's unfortunate."

For the second week in a row, rookie Tommy DeVito replaced the Giants' starting quarterback. Last week against the Jets, he replaced Tyrod Taylor. As Jones' replacement on Sunday, he completed 15 of 20 passes for 175 yards, including a nine-yard touchdown pass in the fourth quarter to Wan'Dale Robinson for the Giants' only points. DeVito also threw two second-quarter interceptions that the Raiders turned into 10 points.

"We're not going to feel sorry for ourselves by any means," DeVito said. "Obviously, things happen. They came out with energy; they played good football. I had two turnovers which led to points. That does not help, certainly, for our defense. Offensively, we have to execute more, come out and make plays, and I need to make more plays."

Las Vegas led 7-0 after one quarter and 24-0 at halftime as they won their first game under interim coach Antonio Pierce, the former Giants linebacker.

"It definitely sucks, but got to be a pro about it, make no excuses," said running back Saquon Barkeley, who rushed for 90 yards and added 23 yards on three receptions. "Still got a long season ahead of us. Obviously, I'm not happy that we're 2-7 with everything going on right now, but we get on a flight, rest up and get ready for next week (when they face the Cowboys in Dallas)."

Jones wasn't the only Giants player to leave with an injury. Adoree' Jackson suffered a concussion in the second half. Tackle Evan Neal, who had missed two games with a right ankle injury, was replaced late in this one after hurting his left ankle. The Giants were without Darren Waller, their leading receiver who has a hamstring injury, and kicker Graham Gano, who is out with a knee injury. They have been placed on injured reserve, as was Taylor.

"It's horrible," Neal said of the numerous injuries. "Especially how well we were doing the previous year and where we're at now, it's definitely not ideal. But sometimes, it's just the nature of this business. All we can do is move forward, move on to the next week, go to work the next day, and make do with what we have."

Jones was actually hurt on the final play of the first quarter, when his right knee bent oddly as he was sacked for a 7-yard loss by Maxx Crosby. Between quarters, Jones went to the sideline and said he was fit to continue.

"He felt like he buckled and then he was running it off," Daboll said. "We went over to him, we talked to him, and he said, 'Nah, I'm good' and then went back in. He obviously wasn't.

"We (coaches and trainers) all talked to him. We said, 'How are you doing?' He said, 'I'm good. I'm good.' And then he was jogging back and forth and said, 'I'm good.'"

The next play proved he wasn't. Jones took a shotgun snap and was backpedaling to look for a receiver when he fell to the ground with no one within five yards of him. He walked off under his own power and went directly to the medical tent on the Giants' sideline. After several minutes there, Jones left the field for further observation. The Giants announced at the start of the third quarter that Jones would not return.

On came DeVito, who on his first play threw a pass to Daniel Bellinger that gained 11 yards – or 12 more yards than he threw for in his debut last week against the Jets.

"It was the same deal as last week, really," DeVito said. "Last week when Ty went down and was kind of slow to get up, everybody kind of looks around at me, 'Hey, get ready to go get some snaps.' Same deal this week. DJ went down right before that first quarter, and the first quarter played out and he said he was good and went out there and then went down again. So, I took a couple snaps with John Michael (Schmitz Jr.), just staying the course."

The Giants' only successful possession was an 11-play, 84-yard march that spanned the third and fourth quarters and ended with DeVito's first career touchdown pass, to Robinson, who was open in the back of the end zone. The Giants' 2-point try was unsuccessful, leaving them in a 27-6 hole.

"We were down, so we weren't able to really celebrate or anything like that," DeVito said. "But that drive, and I think the drive before, you saw us move the ball down the field. I think the offense started to click at that point, but I guess we clicked too late."

The Raiders scored on a 17-yard end around by Jakobi Myers, two short touchdown runs by Josh Jacobs, and three Daniel Carlson field goals. Rookie quarterback Aidan O'Connell completed 16 of 25 passes for 209 yards, no interceptions, and was never sacked.

"They did a good job early in the game running the ball and hitting some big plays," Daboll said. "They took advantage of the opportunities that they had. I thought they did a good job. I thought their quarterback played well, the receivers got open and caught the ball and made some big plays down the field. They did a good job offensively. I give them credit."

Now, the Giants wait for the results of Jones' medical tests to learn who will be their quarterback going forward. If Jones is sidelined, the Giants' only healthy passers are DeVito and veteran Matt Barkley, who is on the practice squad.

If it's the undrafted rookie DeVito, Daboll and Co. will do everything they can to help him succeed.

"Any quarterback we have in, whether it was Tyrod or Daniel, or in this case DeVito, we always try to tailor to what those guys do well and what they prefer," Daboll said. "The quarterback position is an important position. So, definitely if DeVito is the guy, you tailor stuff toward him."

Has DeVito processed that he might be the Giants' quarterback beginning next week?

"I just take it one day at a time," he said. "I don't know the decisions being made outside of right now and what's going on. I can only control what I can control. I go in, watch the film, get better and continue to do that each and every day."

It's a good start.