Ladies and gentlemen, we have ourselves a series.

With one fabulous quarter by Phoenix in Monday’s Game 4, and one unexpected cheap shot to finish things off, the Western Conference semifinals went from an easy walkover for San Antonio to the heated, nasty battle that everyone expected between what are arguably the two best teams in basketball.

The nasty part came to the forefront late, as Robert Horry’s hard foul on Steve Nash with 18 seconds left resulted in his ejection and a suspension for tonight’s Game 5 in Phoenix and Game 6 Friday in San Antonio. But the Suns may end up paying the bigger price — Phoenix’s Amare Stoudemire and Boris Diaw left the bench area after Horry’s foul, which by rule resulted in an automatic one-game suspension from the league office.

Regardless of its implications for Game 5, the Game 4 win was absolutely enormous for Phoenix. It didn’t seem possible when the Suns trailed by 11 points early in the fourth quarter, especially since the Spurs seemed in total control. Tim Duncan was again having his way with the Suns’ post defenders, Bruce Bowen was busy harassing Steve Nash into an eight-turnover evening, and San Antonio role players like Brent Barry and Michael Finley were draining 3-point daggers.

But Mike D’Antoni won the battle of tactics against San Antonio’s Gregg Popovich, and perhaps more important, his team out-executed the Spurs down the stretch. D’Antoni’s key shift was to stop singlecovering Duncan and start sending double teams in his direction. That slowed down some of his momentum (Duncan had two points in the final 10 minutes), and foul trouble took care of the rest.

Duncan got his fifth foul with 6:18 and checked out soon after with 5:35 to play. That’s when Popovich made a rare mistake, leaving Duncan on the pine too long while the Suns started clawing their way back. By the time Duncan re-entered, with a mere 2:42 left on the clock, San Antonio’s lead had been whittled to three points. That was far too conservative a play. With so little time left after the fifth foul, Duncan shouldn’t have been out more than a minute, if at all.

Meanwhile, D’Antoni’s change in defensive tactics allowed him to play a more offensive lineup. Out went Kurt Thomas and in went Amare Stoudemire, who played the final four minutes alongside Shawn Marion, Leandro Barbosa, Nash, and Bell — the Suns’ best offensive unit.

Yet the double-teaming allowed Phoenix to excel defensively as well, as the Spurs mustered only one score in their final nine possessions — a lay-up by Duncan — and even that came only after Phoenix had blocked a shot on the Spurs’ first try. As a result, the Suns closed the game on a 16–2 run following the substitution for Thomas, allowing them to climb back into the series against an opponent that’s seemed to have their number ever since Nash moved to Phoenix.

However, Phoenix may face an even more daunting task in Game 5. The Suns can get over losing Diaw. He only played 15 minutes on Monday night, and James Jones could take over his playing time and provide roughly the same productivity.

But Stoudemire? Without him the Suns are a gun short, as they showed a year ago in the Western Conference finals against Dallas. I don’t think what he did was at all egregious or suspension-worthy, especially in contrast to Horry’s cheap shot, but the letter of the law has always been that anybody who leaves the bench area gets an automatic suspension — something Knicks fans are all too familiar with.

It goes without saying that this is a horrible twist of fate for the Suns. Yet I wonder if the bigger takeaway is that it was the Spurs, not the Suns, who lost their cool this time. Horry is perhaps the most unflappable players on one of the league’s coolest teams under pressure, so watching him lose his head in the final minute was notable.

Moreover, while Horry lost his head — and is now suspended for two games himself — another Spur lost his game. Sixth man Manu Ginobili seems totally rattled by Bell’s defense. He shot 3-for-14 on Monday, continuing what has been a miserable postseason for him. For the playoffs he’s shooting 32.7%, has only one 20-point game, and has yet to make more than half his shots in a contest. In the Phoenix series he’s been even worse — just 31.4%, and with comparatively few free throws (15) by his standards.

Meanwhile, for all their complaints about the physical play and the antics of Bowen, it sure seems to me that Phoenix has shown a fire in this series that we haven’t seen from them in previous postseasons. It wasn’t just the mettle they showed in Game 4 either — the Suns played harder than I’ve ever seen them play in their blowout win in Game 2, diving for loose balls, racing up and down the floor and generally playing like their lives depended on the outcome.

So for now, at least, it’s advantage Phoenix. The Suns have outscored the Spurs by a total of 14 points over the first four games, and will have two of the final three contests in their own arena. Of course, the wild card in all this is that Phoenix must win at home tonight without two of its frontcourt players, leaving them more vulnerable than ever to Duncan’s superlative lowpost game.

But the Suns have already learned the hard way that the playoffs aren’t always fair—witness the injuries to Bell and Joe Johnson the past two years that sidetracked them in the conference finals. Historically, perhaps no franchise has been as snakebit as this one, and the Stoudemire suspension may go down as another example.

However, I sense a difference this time — that the Suns may finally have both the spirit and talent to overcome those setbacks, something I don’t recall thinking in postseasons past. Yes, Phoenix still has to win twice more to advance, and that would be a daunting task against this opponent even if Stoudemire hadn’t been suspended. But if the Suns do end up getting past the Spurs and going on to win their first-ever NBA championship, I’m pretty sure they’ll look at the fourth quarter of Game 4 as the turning point.

jhollinger@nysun.com