Rivera is one save away from becoming just the second closer to reach 600 and is only two shy of tying Trevor Hoffman's all-time mark.
"It's amazing that it hasn't drawn more attention," Yankees manager Joe Girardi said on Monday. "Six hundred saves, there's only one other guy to do it and we don't know if there will ever be another guy to do it in our lifetime."
The incredible closer's services were not needed on Monday, as Mark Teixeira and Chris Dickerson homered off Felix Hernandez in the fourth inning, and Phil Hughes pitched six strong frames in New York's 9-3 win.
Robinson Cano stroked a three-run double, as the Yankees widened their lead to four games over Boston in the AL East. The Yankees, who snapped a four-game skid on Sunday in Anaheim, compiled 14 hits, three from Cano.
Hughes (5-5) ended a three-game winless stretch by limiting Seattle to five hits and a run.
"I'd like to be ahead a little more and maybe get some quicker outs so I can go deep in the game, but other than that, you can't argue, especially when we get the kind of run support against Felix," Hughes said. "Coming into this game you never imagine that you're going to get six runs, you're hoping for one or two and then keep them close. That was a nice luxury to have tonight and fortunately caught some breaks there in the middle innings and kept them off the scoreboard."
Hernandez (14-12), who had won his previous three starts, was charged with nine hits and six runs over six innings. He entered the night with a five-game winning streak vs. the Yankees, the longest ever by a Mariners pitcher.
"It looked like he just kept missing out over the plate a little bit," Mariners manager Eric Wedge said. "His stuff was good, they just started rolling it, one after the other in that fourth inning."
Miguel Olivo clubbed a two-run homer in the opener of this three-game series, but the Mariners fell to 3-9 this month.
Heading to the hill for the Yankees tonight will be inconsistent righty A.J. Burnett, who is 9-11 with a 5.27 ERA. Burnett did not get a decision on Wednesday against Baltimore, as he allowed four runs and seven hits with four walks in six innings of a 5-4 loss.
Burnett is 2-2 in seven starts versus the Mariners with a 3.80 ERA.
Seattle, meanwhile, will counter with lefty Charles Furbush, who has dropped his last four starts. Furbush lost to Anaheim on Wednesday, allowing three runs and five hits in 7 1/3 innings, as he fell to 3-8 on the year to go along with a 4.84 ERA.
He has never faced the Yankees.
The Yankees have won four of their seven matchups with the Mariners this season.