EAST RUTHERFORD, N.J. — The New York Giants’ preseason showing was worrisome, and rightfully so.

Quarterback Eli Manning struggled with executing his new footwork, the receivers weren’t on the same page, the offensive line was undergoing changes virtually every day in practice and there were endless questions about the tight ends.

Thankfully, the preseason is in the past and the Giants offense has gotten back on the right track.

One of the impressive things about the offense’s production, according to coach Tom Coughlin, was its ability to cover when in the opponent’s territory.

“In the last two games combined, we’ve had 10 drives start in the opponent’s territory, six touchdowns and two field goals,” Coughlin noted.

“The opponent has started zero drives in our territory, which tells you a little bit of something about doing a better job with ball security, taking care of the ball, and then also on the other hand, the takeaways have improved tremendously in the last two weeks.”

One of the key developments in the offense’s progress has been the play of the offensive line. In Week 1, the line gave up two sacks and nine quarterback hits to an aggressive Lions defense, who also held the Giants to 216 yards of offense.

In the three games since then, the offensive line has allowed four sacks and four quarterback hits and has helped contribute to the Giants averaging 403 net yards per game on offense.

“We’ve played this one group together for a few weeks and they experienced a little bit of success a week ago that has done a lot for them,” Coughlin said of the offensive line’s rapid jelling process.

“To win at home against a Houston team, to rush the ball the way we did, I think that the offensive linemen took great pride in that and I think once that starts to develop and you get that group that has the camaraderie and the pride in what they want to accomplish, that helps an awful lot.”

The biggest and perhaps most surprising difference on the offense has been the emergence of second-year tight end Larry Donnell, who receiver Victor Cruz believes was key to the offense’s turnaround after the 35-14 beat down by the Lions in Week 1.

“I think when Larry Donnell started to come on and catch the ball and make some plays for us, I think that is when things kind of shifted and things went in our way a little bit,” Cruz said via conference call.

“It was definitely something that we needed to happen, someone to step up and make some big plays, and Larry Donnell has done that for us.”

Donnell currently leads the Giants with four touchdowns, three of which came in the team’s 45-14 blowout win over Washington on Thursday night.

He is also the team leader in receptions with 25, and his 236 receiving yards are just 63 behind Cruz’s team-leading 299.

Coughlin always believed that because of Donnell’s athleticism, he could be a special player if he worked at his craft. So far, the coach has not been disappointed.

“There’s a lot to have to accomplish, the blocking part of it, the knowledge of the game, the routes and how to run them from that inside position against defenders, whether they be big, strong linebacker types, safety types, whatever it might be,” he said.

“There’s a young, inexperienced player that’s eager to learn and has athleticism, has speed, has outstanding hands, so we’ve always had a high level of expectation for this player and how he can develop. He has started along those lines. There’s a long way to go, but it doesn’t change what we think this player can be.”

Cruz, who compared Donnell’s skill set to Martellus Bennett, who was with the Giants in 2012 before leaving via free agency to join the Bears, said it was just a matter of time before Donnell, who is in his second season, came into his own.

“I know exactly what type of athlete he is. I see him in practice every day. I see the type of plays that he makes, and I know it is just a matter of him getting his opportunity and him making the best of it,” he said.

Cruz noted that Donnell, a former basketball player, has a certain athleticism about his play that allows him to be successful in this style of offense.

“I think he understands how to go up and get the ball wherever it is and understand how to position his body. I think that is because of his basketball background,” he said.

The 6-foot-6, 265-pound Donnell, who wasn’t heard from much last season largely because he fell behind in his learning thanks to a broken foot that kept him out of the offseason workouts, has caught the league by storm.

According to the stats kept by Pro Football Focus, Donnell has caught 80.6 percent of the passes thrown his way, tops of all tight ends who have played in 75 percent of their team’s offensive snaps.

His four touchdown catches tie him with Bennett for second in the NFL among all tight ends and are one behind league leader Julius Thomas of the Broncos

“I knew once he got it this year, with the style of offense that we have, it definitely makes well for an athletic tight end to do some positive things,” Coughlin said. “I think he filled that void for us.”