Nova did his part, getting back on the victorious path one start after having a streak of 15 straight winning decisions snapped to remain undefeated in his career against the Rays.
Raul Ibanez homered twice and Curtis Granderson slugged a solo shot, his team-leading 10th, as the Yankees toppled a tough James Shields and encountered a save situation for the first time since Rivera's season-ending right knee injury last week in Kansas City.
"I was a little nervous, once again knowing you don't have anyone behind you -- or at least you don't have Mariano behind you," Robertson said. "I would have liked for it to be a real quick inning; it started off real well, but walks kill you."
Trusted with keeping the lead from Nova's seven strong innings of eight-strikeout ball intact, Robertson loaded the bases before striking out Carlos Pena for his fourth career save.
How rare is it not to have No. 42 jogging out of the bullpen in that spot? Since Rivera took over the closer's role in 1997, Ramiro Mendoza ranks second in Yankees saves with 16. The Yankees hope Robertson's chances aren't all this nerve-wracking.
"I think it's important for him," said Joe Girardi, who won his 400th game as Yankees manager. "He looked comfortable. He doesn't seem comfortable unless the bases are loaded. He threw strikes; that's the most important thing. If he was all over the place, I would have had concern, but he wasn't."
Neither was Nova, who looked sharp in what he agreed may have been his best start of the year thus far. The righty carried some purpose -- and more importantly, all of his pitches, in effective fashion -- as he carved up Tampa Bay.
Jose Molina slugged a solo sixth-inning home run, reminiscent of the one he cracked in pinstripes on the final night of the old Yankee Stadium on Sept. 21, 2008, and Luke Scott hit a solo blast in the seventh. That accounted for the only damage against Nova, who scattered six hits and walked two, throwing 59 of his 93 pitches for strikes.
The Rays had a chance to get more off Nova in their half of the seventh, but third-base coach Tom Foley held Jeff Keppinger on Will Rhymes' double into the right-field corner.
Nova rebounded to get Sean Rodriguez to fly out to right field and Keppinger held on Nick Swisher's great throw to the plate, and Molina struck out swinging to end the threat.
"I liked the way he was throwing the baseball, and I just felt like he was going to get an out," said Girardi, who had Rafael Soriano warming. "I liked his stuff and I felt like he was going to get it done."
Shields, as usual, presented a tough challenge and limited the Yankees to just four hits in six innings. But a pair of grooved offerings was enough to send Shields to the visitors' clubhouse trailing, as the right-hander had his string of six straight winning starts, dating to last season, snapped.
Ibanez connected for a fourth-inning homer with Nick Swisher aboard and Granderson -- after entering the game 3-for-46 lifetime against Shields -- slugged a solo shot on the 10th pitch of his at-bat in the fifth.
"That's what this team does -- they fight," Shields said. "They have good at-bats every single game. You have to kind of roll with it. I thought both of those home runs were pretty good pitches."
New York added breathing room opening the seventh, as Ibanez greeted reliever Burke Badenhop with a solo home run that clanged off the right-field foul pole, marking the veteran's 15th career multihomer game.
"I just tried not to do too much," Ibanez said. "I just tried to put an easy swing on the ball. Fortunately, I caught them pretty good and they went out of the park."
The late innings provided a glimpse of what the post-Rivera era might look like. Soriano surrendered a triple to Ben Zobrist in the top of the eighth, and the right-hander's wild pitch three batters later allowed Zobrist to cut the Yankees' lead to 4-3.
But Mark Teixeira added a one-out double in the eighth that scored Alex Rodriguez, who led off the inning with a single and advanced to second when center fielder B.J. Upton misplayed the third baseman's single.
"Every game is important, and I know we've had tough moments," Nova said. "But every time you win is a great win, especially with those guys in the same division. They've been playing really well. Every time we win against them, I'll take it."