NEW YORK -- Felix Hernandez was long gone, after hitting the first grand slam by a pitcher in Interleague history, then spraining his ankle. And the two relievers most likely to be used to end a game were unavailable for the Mariners' series opener against the Mets on Monday night.

So veteran left-hander Arthur Rhodes became the last line of defense, and he came through in a big way.

Rhodes sauntered in from the bullpen and struck out the two batters he faced in the ninth inning, securing the Mariners' 5-2 victory over the Mets in front of an announced crowd of 49,789 at Shea Stadium.

It was an emotional roller-coaster night for Seattle.

They received an unexpected boost in the second inning, when right-handed starter Hernandez swung at the first pitch he saw from Mets left-hander Johan Santana and became the first pitcher in Mariners history to hit a homer.

But in the fifth inning, with the Mariners ahead by five runs, Hernandez sprained his left ankle while covering home plate on a run-scoring wild pitch. The pain finally became too much and Felix departed, one out away from qualifying for his seventh victory.

The win went to left-handed reliever Ryan Rowland-Smith, who retired all six batters he faced in the seventh and eighth innings, before things became a little nerve-racking in the ninth.

With one run in and two runners on base, Rhodes fanned left-handed-hitting Carlos Delgado swinging and snuck a game-ending pitch past right-handed-hitting Damion Easley to notch his first save since Aug. 29, 2006, when he pitched for the Phillies.

"It's tough to get that third out in the ninth inning," Mariners interim manager Jim Riggleman said. "That's why they pay those guys so much money. It's tough to find someone who can come in and do that, and Arthur answered the call tonight."

Rhodes is not the Mariners' primary closer. He's not even the secondary closer.

But with closer J.J. Putz on the 15-day disabled list and backup door slammer Brandon Morrow unavailable for the fourth consecutive game because of back spasms suffered last Wednesday night, Riggleman turned to one of his most experienced relievers for two outs.

Rhodes did the job, and he said the save was secondary to the victory.

"I went out there and made some pitches that I needed," he said. "I didn't let Delgado hit a home run and put some runs on the board."

That would have erased the four-run lead right-hander Sean Green had to start the inning. Two singles, a walk and a fielder's choice had Mets fans anticipating a remarkable comeback victory.

"I faced [Delgado] a lot when he was in the [American League], and I faced him a couple of times in the [National League]," Rhodes said. "I know him pretty well."

It is even more one-sided in Rhodes' favor. Delgado is now 5-for-29 with two doubles, one home run, four RBIs and eight strikeouts against the 38-year-old lefty.

The Mariners (27-49) won for the second time on the nine-game, three-city Interleague road trip. They also won the series opener against the Braves before losing the next two.

A win either Tuesday or Wednesday night would give the Mariners a series edge, something they need.

And just like the win over the Braves, the starting pitcher had to leave the game because of an injury. In Atlanta, lefty Erik Bedard departed after the third inning because of back spasms.

This time, it was Hernandez being helped off the field with a sprained left ankle.

Right-hander Roy Corcoran finished the inning and pitched a scoreless sixth inning before Rowland-Smith took over.

As big as Hernandez's grand slam was -- and it was huge -- the way center fielder Willie Bloomquist sprinted to first base -- after hitting what appeared to be a routine inning-ending grounder to Mets third baseman David Wright -- kept the second inning alive.

"The key to the inning was Hernandez's home run," Riggleman said, "but Willie hustling on the ball he hit was another key. You tell guys all the time, 'When you hit a ground ball, you run hard.'

"It's human nature not to go as hard as you can, but he did and he beat it out. At the time, we're thinking, 'Great, the pitcher hits, we turn the lineup over, and Ichiro leads off the next inning.'"

One pitch later, Hernandez was circling the bases behind three teammates.

"We wanted to make sure that Felix knew it was early in the ballgame and he had a lot of pitching to do," Riggleman said. "The way he was throwing, you would have liked to see him stay out there and throw his 100-something pitches and get real deep into the game."

That didn't happen, but as Riggleman acknowledged afterward, it could have been a lot worse.