For his opening act, Rex Grossman impressed. He did what was needed in the Washington Redskins’ 28-14 season-opening victory over the New York Giants. Now, Grossman must do it again. And again and again. In the unforgiving week-to-week world of the NFL, Grossman is only as good as his next game.

Granted, he’s off to a superb start.

Grossman had 305 yards passing, playing a big role as the Redskins ended a six-game losing streak to their NFC East rivals. He threw two touchdown passes without an interception en route to a strong 110.5 passer rating.

Turnover-prone throughout his long run with the Chicago Bears, Grossman fumbled while being sacked early in the fourth quarter Sunday, and the Giants recovered the ball. It was just one of those days, however, when no problem seemed too big for the Redskins. On the possession after Grossman fumbled, Washington blocked a New York field-goal attempt.

“It was my fault,” Grossman said of the fumble. “It was just a bad play.”

Often while Grossman was leading the Bears, his first major miscue led to many more. The notoriously streaky quarterback would go on a roll in the wrong direction.

Not against the Giants.

After the blocked field goal, Grossman was smooth, directing a 10-play, 70-yard touchdown to all but clinch the game. His four-yard scoring pass to wide receiver Jabar Gaffney was a nice closing touch on his fourth career 300-yard game — three of which have come in his first four starts with Washington.

Thing is, Grossman has enjoyed success previously in the NFL only to regress, so consistency will be the key. Grossman must prove he’s capable of seizing the second chance Mike Shanahan has given him.

Week 1 is done for the Redskins. At least 15 more hurdles are still blocking Grossman’s path to the finish. There’s no time to celebrate. Not with the Redskins suddenly having big expectations again and John Beck, who lost the quarterback battle to Grossman, continuing to work hard in hopes of getting another chance. Although Beck failed to keep pace with Grossman in their two-man preseason race, Shanahan still evaluates them daily.

Undoubtedly, Grossman’s performance pleased Redskins fans, some of whom probably wondered whether he truly was the best choice to lead Washington even after Shanahan made the call.

But after the Donovan McNabb debacle of last season and the franchise’s long-unfulfilled desire for stability at the game’s most important position, the Redskins and their fans are eager for Grossman to lock down the job, at least for the season.

Responding about as well as possible in his first test, Grossman, and Shanahan, should be encouraged.

Playing for a perfectionist such as Shanahan, there’s always room for improvement. In the coming days, Grossman may observe things on film that disappoint him. He could have performed even better.

But the Giants have dominated the Redskins recently. Grossman delivered, as Washington ended a frustrating stretch against a divisional opponent. He helped Shanahan get off to a good start in his second season after 2010’s 6-10 soap opera.

That’s something.

It was apparent in the preseason Washington should be a better team this year. The Redskins possess more potential than in previous seasons because they have more talent. Making the correct decision on the quarterback is key for Washington to show how far it has come. In the NFL, everything works best if the right guy occupies the most important position.

On sports-talk radio and the Internet, Grossman now stands atop a pedestal. As long as the Redskins continue to win and Grossman plays well, he’ll maintain his high standing. A slip up or two, though, watch out. The positive chatter could end quickly. It did for many others who previously held the job Grossman does at the moment.

In the preseason, Grossman’s top moments were as good as Beck’s best outings. When Grossman and Beck weren’t in good form, Grossman still inspired more confidence in his coaches and teammates.

That’s what happens when one guy has started in a Super Bowl and the other has started only four games in his first four seasons in the NFL.

On the Redskins’ first two series Sunday, Grossman failed to complete a pass, misfiring on his first four attempts. The third time Washington had the ball, though, he started to get it together and kept it going.

“Things don’t always work out the way you think they will to start the game,” Grossman said. “But you always have confidence that, eventually, you’ll get into a rhythm.

It’s about performing well each game. Grossman knows how this works. It’s all there for the taking. He just has to keep being better than he ever has been.