The last great rivalry today?

NEW YORK -- It's good to be a sofa-bound tennis fanatic these days. Well, that is, assuming you enjoy the glorious rivalries that have evolved, devolved and re-emerged over the past decade. We've been flooded with some of the best this game has ever had to offer, which is no small feat given the large footprints today's players have followed.

But this era is going through a bit of a remodeling stage. Sure, we've been spoiled by a bloated state of breathtaking tennis, but we're amid something we haven't experienced in a decade.

Let's call it The Stan Effect.

You know what we're talking about. Stanislas Wawrinka, naturally. He became only the second player outside the game's precious big four to win a Grand Slam since 2005. This title, though, represented something bigger than Wawrinka's accomplishment. It revealed a certain fragility from the game's penthouse players that we haven't seen in earnest in more than 10 years.

This current era of dominance has lasted so long, it almost seems surreal that any semblance of disbandment could be coming to a court near you. In 2003, Roger Federer began a quest, one that evolved into a lasting legacy. Win or lose, we've been entrenched in a generation in which the entertainment value has equaled the unparalleled results.

So when the entrance smoke filled a packed house at Madison Square Garden on Monday night and the two 26-year-old participants in the main event, Novak Djokovic and Andy Murray, emerged, we were left wondering something a bit troubling: Are they the last hope to carry on this era of dominance?

"I mean, we've played in quite a few big ones over the past few years," Murray said in a conference call earlier this week. "We've played a couple of great matches in Australia as well, but, I mean, from my side, that was my first Grand Slam for me, and the way that the match went as well -- where I was up two sets to love and then he came back and then to come through winning that -- it was probably my best one against him."

If you think we're discounting more magical moments from Rafael Nadal and Federer, we're certainly not. But Nadal is a year older than Djokovic and Murray -- and, arguably, a dog year older in on-court mileage when you consider the pounding his legs take. Federer played majestically in Dubai this past week in winning his first event of the year, but we've seen his results plummet, especially last season, in which he fell in the second round at Wimbledon and the fourth in New York. The two elder statesmen of the big four have been marred by setbacks. Nadal with his 7½-month layoff in 2012-2013 and Federer, as mentioned, with his sudden Slam shortcomings and squirrely back. At some point, age, injury, or both, will catch up to them. It has to, right?

Djokovic and Murray were born just seven days apart, and their long, rich history promises many more compelling moments.

"We've played each other since we were 11 years old, so we've known each other a long time, competed against each other all through the juniors and, obviously, now in some of the biggest tournaments in the world and the Grand Slam," Murray said Monday. "So our games have obviously changed a lot; we've obviously grown up a lot. I think that the one thing that has changed in tennis is the athleticism, and I've played against Novak and know what it's like playing against him on the other side, and he's an incredible athlete and moves exceptionally well."

But Murray and Djokovic, too, have both endured trying times. This season, Djokovic was whisked out of the Aussie Open by Wawrinka, and then Federer stopped the world No. 2 in Dubai. After snaring three Slams in 2011, Djokovic has won only two of the past nine. As for Murray, he ended 2013 on the operating table to repair a nagging back and then lost to that certain 17-time Grand Slam winner at the Aussie.

"Roger played a great tournament in Dubai," Djokovic said. "He's No. 7 or 8 in the world, but, regardless of that, he's a 17-time Grand Slam winner, and he's one of the best players in the history of the game and you can never sign him out. He always plays really well, and you always have to be on top of your game to win against him, no matter what surface you play on. It's Roger Federer across the net.

"Of course, Rafa is there and you have young guys like [Grigor] Dimitrov and [Milos] Raonic and [Jerzy] Janowicz, the big servers. It's a very interesting time for men's tennis at the moment, and it's just the beginning of the season, so it's too early to predict who can finish No. 1 or who can win Grand Slams, but I think it's a bigger group that can win Grand Slams -- not just the four us."

And then, there's the ceiling question. Has Djokovic reached his? In 2011, he won three major titles, but in the past nine, just two. Reason to worry? For Murray, he snapped a career oh-fer in 2012 at the US Open and, of course, thrilled his home crowd with a Wimbledon win a year ago. But with a so-so 12-4 record, and with one semifinal appearance in four events, Murray's game is lacking the gusto it had six months ago.

And then there's Raonic and Dimitrov and Janowicz. Are they ready to infiltrate prime-time programming? Is The Stan Effect a real thing? Dare we say that ghastly P-word -- parity -- is slowly poaching on the game? Or is it all just a brief interlude? Who knows?

A lot of questions with few answers, so it seems.

But one thing is clear: There is no clarity two months into 2014. What we can say is that we need to appreciate what we're watching, because, sooner or later, when Djokovic, Murray and their big-four brethren are no longer dominating, the game could make a beeline into obscurity, and that's going to be a tough watch for the sofa dudes.