Last spring, the Golden State Warriors seemed to be trudging to their fifth straight season of obscure mediocrity — and then lightning struck. During the final seven weeks of the season, they won 16 of their final 21 games, eking into the playoffs on the final night of the regular season. That’s when it got really interesting: In the biggest upset in NBA playoff history, they ousted the Dallas Mavericks before running out of gas in the second round against the Utah Jazz.

Going into this season, then, it only seemed sensible to figure that the Warriors were going to be a bit better than the mediocre team that played for the first three quarters of the 2006-07 season — but nowhere near the amazing team that seemed to beat the world during the final two months of that season. Utah had shown how to defeat the Warriors, how not to get caught up in their uptempo game, and how to pound their small lineup with inside muscle. This forecast even seemed a tad optimistic when Golden State opened this season with a six-game losing streak. But since then, the fire has returned, and the Warriors have won 12 of 15, including a stunning 96–84 win over San Antonio on Tuesday night.

If they are going to play like this, then it might be time to at least consider Golden State to be one of the elite teams in the Western Conference.

It’s important to remember that strange things happen to good teams on the road — and that the Spurs were without All-Star forward Tim Duncan — but this win was significant on several counts. For one, Duncan’s absence might have been a tad overrated for a team as balanced and well-coached as the Spurs. Without him, the Spurs beat both the Jazz and the Dallas Mavericks, showing that they can withstand a short-term absence from their superstar. Also on Tuesday, Duncan’s replacement, Matt Bonner, posted career highs of 25 points and 17 rebounds; it’s optimistic to assume that they would have gotten much more than that out of Duncan.

What made the game impressive was how the Warriors shut down the Spurs’ leading scorer, Manu Ginobili, who picked up his MVPcaliber game another notch in Duncan’s absence. Ginobili, who scored 37 points in each of the San Antonio wins against Dallas and Utah, was held to a meager 14 points on 4–14 shooting by Golden State. The Warriors accomplished this by marking Ginobili one-on-one, mostly with swingman Stephen Jackson. In addition, Baron Davis, one of the most underrated defenders in the league, put the clamps on Tony Parker, holding him to 11 points on 5–14 shooting.

The game was played at the Spurs’ favored tempo: a slow pace. But the Warrriors won at that pace, and by playing tight defense. The Warriors often play three and four-guard alignments, and these wings patrol the passing lanes as if their lives depended on it — Golden State is one of the best teams in the league at forcing turnovers. Tuesday night, they forced San Antonio into 21 miscues (a season-high), and they completely discombobulated the Spurs’ offense with their defensive intensity during a 30–12 run in the second quarter,.

This marks a big change for Golden State who, typical of most teams helmed by coach Don Nelson, wins with its offense. These Warriors are potent with the ball, ranking seventh in the league in Offensive Efficiency (points per 100 possessions), and they play very fast: Their 97.3 possessions a game is the third-fastest pace in the league.

In many ways, the Warriors’ offense is the “lite” version of that of the Phoenix Suns. They shoot a lot of threes, rarely get to the free throw line, usually field a small lineup, and run at every opportunity. This is the fourth season since Phoenix shocked observers with this style, and no team has done as well as the Warriors in adapting it. It was when the Suns proved that they could win while playing at slower tempos that people took them seriously as a title contender. Is it time to accord similar props to the Warriors?

The case for Golden State is strong. During this 15-game run, they’ve lost only to two top teams, the Boston Celtics and the Orlando Magic, as well as the Los Angeles Lakers, a team that seems to have a hex on the Warriors.

They are building a strong case, but it would be best to see a little more consistency. Their 0–6 start was without Stephen Jackson — a good player, but hardly the kind of player that should have that kind of impact. The Spurs win with Duncan, and they win without him.

What this good stretch shows is that last year’s final two months weren’t a fluke. As San Antonio learned Tuesday night, the Warriors are a good team when playing their game, and they can be a very good team when playing their opponent’s style, too. Picked by most to be a .500 team this year, it’s now fair to project them to win 45 to 50 games (barring a major injury), and they will be a tough matchup for any first-round opponent, especially the slow paced teams in Texas.

mjohnson@nysun.com