OAKLAND, Calif. -- The game was in hand, the series outcome clear, the impenetrable fortress that is Oracle Arena claiming another victim. A dominant first half for the Golden State Warriors felt like nothing short of a formality.

A 60-47 halftime lead for the 73-win, defending-champion, only-lost-twice-at-home-all-year juggernaut?


And then Russell Westbrook happened. In a blur of athleticism, scoring and domination he shook the Warriors to their core and turned a rout into an eventual 108-102 Oklahoma City Thunder stunner. And changed, for now, the course of the Western Conference finals.

It was shocking to see, and not just because we have grown accustomed to Warriors home wins and mostly unfettered postseason greatness. Westbrook's star turn came after he began the game on a 1-of-11 shooting slump that seemed destined to force him to eat those words from earlier in the day about Stephen Curry being "nothing I haven't seen."

What we hadn't expected to see was just this level of Westbrook awfulness in such a key game: A first half that included 1-of-8 shooting, three miserly points, three turnovers. The four steals and eight assists over that stretch seemed, at the time, like statistical consolation prizes.

And what we did see from Westbrook in that third quarter was a new look on his greatness: 19 points on 5-of-9 shooting -- just nine shots -- three assists, three steals, two rebounds and not a single turnover. And, with all that, a whole new swagger in a Thunder team suddenly reanimated.

"Just trying to stay aggressive and find ways to change the game," Westbrook said. "My job isn't just to score. It's to defend, get guys open, whatever it takes to win the game."

He did just that -- everything. All it took to win. After a huge 3-pointer ignited him, Westbrook was a man on fire. He finished with a line of 27 points, six rebounds, 12 assists and seven steals. He attacked, time after time, and ended the game with almost as many free-throw attempts (14) as the entire Warriors team (17), and made just as many of them (11).

"When players of his caliber aren't playing well, aren't shooting the ball well, sometimes it only takes one to go in," Curry said. "I have the same mentality. And you know they're not going to stop no matter how they're playing."

That is the test now: stopping Westbrook. Because his Game 1 performance was remarkable as much for how it lifted and recalibrated a struggling team as for who it helped beat and where it did it.

The recipe for a Thunder series win? Great performances from Kevin Durant and Westbrook, take care of the ball, win the paint, play the kind of defensive grit they've shown this postseason but didn't in the regular season, and win the rebound game against a go-small squad. Oh, and somehow win at Oracle, a feat only two other teams had figured out how to do this season.

Durant finished just 10-of-30. Westbrook, as noted, couldn't shoot in the first half -- and his team followed suit: Over that span the Thunder had 10 turnovers, were out-rebounded 25-22 and lost the points in the point battle 28-22. They gave up 60 points.

Game, set, match. Or so it seemed.

"Russell was the catalyst, getting to the rim, finishing," Durant said of his teammate's turnaround. "We just followed that lead and played hard on the defensive end. Withstood a couple leads they had and just kept playing through it."

Followed his lead? Did they ever.

In the second half, the Thunder had just one turnover, dominated the boards 30-19, evened up the points in the paint score 18-18 and held the Warriors to just 42 points. And with it they claimed a 1-0 series.

As the San Antonio Spurs and the Thunder know well, that's far from an unfettered path to a series win and, in this case, a Finals berth. But Monday night's game nonetheless could have lasting and seismic implications -- for the course of this series, the balance of power in the league, the future of the NBA and how we assess and remember this Warriors team.

Much beyond -- or, I should say, inseparable from -- the championship itself is at stake: The future of Kevin Durant, the legacy of the NBA's only 73-win regular season, and what now feels like the invincibility of those who have mastered the go-small approach.

That, even if for a fleeting moment, is what Westbrook led his team toward: A future with Durant, a reminder that going big can still win in the National Basketball Association, and the possibility that the Warriors were indeed vulnerable despite their greatness.

It's just one game. But for now, at least, it's a game that puts Westbrook and the Thunder in control of a series few of us believed they'd even reach.

Russell Westbrook willed his Thunder to victory in Game 1. Getty Images