The New York Giants had faced mostly a bunch of backup quarterbacks and backups masquerading as starters through the first 11 weeks. But this was Russell Wilson. This was a step up in class and destined to provide the ultimate test.

The Giants entered Sunday's 17-12 win over the Seattle Seahawks 10th in yards per game allowed and tied for ninth in points. But they hadn’t faced anyone like Wilson or the Seahawks (8-4), who came into the contest averaging over 30 points per game.

Defensive coordinator Patrick Graham and his group didn't just pass the test. They aced it for their fourth straight win. The Giants (5-7) got their first win this season against a team with a winning record and took over sole possession of first place in the NFC East with four weeks remaining.

They did it by making the Seahawks' offense look ordinary, allowing just 12 points and 327 total yards. They made Wilson look indecisive. The Pro Bowl quarterback was holding the ball longer than usual, leading to five sacks and a pedestrian afternoon that wasn't even as good as his numbers (27-of-43 for 263 yards with a touchdown and an interception) suggest.

It was the latest example of this Giants defense continuing to make strides. It doesn't seem to matter that they don't have any of their top edge rushers available. Rookies Carter Coughlin and Cam Brown were making key plays on Sunday. Defensive lineman Leonard Williams continues adding to the best season of his career.

Williams had 2.5 sacks and now has a career-high 8.5 this season. He had half a sack last season.

But it's at the back end where the Giants have seen the most growth. The missed assignments that had plagued this team for years and early this season have disappeared.

Cornerback James Bradberry kept Seahawks star wide receiver DK Metcalf (five catches for 80 yards) in check most of the afternoon. Isaac Yiadom has settled in at the other cornerback spot and had some key tackles and pass breakups Sunday.

The Giants' defense hasn't allowed over 20 points during the team's four-game winning streak. It is the reason this team is in first place at the start of December. And it proved Sunday in Seattle that it's not a fluke.

QB Breakdown: It wasn't a pretty performance by quarterback Colt McCoy, starting in place of the injured Daniel Jones.

McCoy finished 13-of-22 for 105 yards with one touchdown pass and an interception. But he made big throws to Darius Slayton and Evan Engram for first downs that kept the clock ticking.

McCoy did what the Giants asked of him for most of the afternoon. He kept them in the game and didn't make the big mistake. He didn't throw a pass longer than 20 yards until there was less than two minutes remaining.

It was what the Giants wanted during one week of fill-in duty. Jones, who suffered a hamstring injury during last Sunday's win over the Bengals, was close to being ready for Sunday's game and is expected back next week when the Giants host the now-struggling Arizona Cardinals.

Pivotal play: Wayne Gallman's 60-yard run at 9:04 of the third quarter. The Giants' offense was nonexistent in the first half and Gallman had 6 yards on four carries after being so good in recent weeks. It all changed early in the third quarter, when the Giants called a run on third-and-7 from their own 23.

It was a power run that had right guard Kevin Zeitler pulling. He got a key block on former Giant Damon Harrison. Left guard Shane Lemieux and tackle Andrew Thomas got to the outside and sealed a hole with the help of wide receiver Austin Mack and tight end Kaden Smith.

Gallman found the gap outside the left hash and raced down the sideline. He was tackled at the Seattle 17 on the longest run of his career.

The Giants got into the end zone two plays later, the first of Alfred Morris' two touchdowns. They converted the two-point conversion to take an 8-5 lead and never looked back. Gallman's run changed the game.

He finished with a career-high 135 yards rushing and the Giants rushed for a season-best 190 yards as a team. That long run got them started.

Troubling trend: The Giants' usually steady special teams had another rough game. It was the second week in a row, after allowing a 103-yard kickoff return for a touchdown last Sunday to the Cincinnati Bengals. It prompted special teams coordinator Thomas McGaughey during the week to call it the worst coverage day of his career.

This week it was the Giants' punt team that was a mess. They were flagged for a pair of false starts and allowed a blocked punt late in the first half. Fortunately for them, Seattle's Penny Hart failed to recover it inbounds. His arm was out of bounds, resulting in a safety instead of a touchdown, which gave Seattle a 5-0 lead at the half.