Russell Westbrook and Kevin Durant were left with plenty to think about after yet another blown fourth quarter lead led to Golden State beating Oklahoma City Thursday night in Oakland, sending the Thunder to a sixth loss in eight games since the all-star Break. (AP Photo/Marcio Jose Sanchez)

Two weeks ago, the Oklahoma City Thunder came out of the all-star break as one of a few clear contenders for this year’s NBA championship.

After losing six of their eight games since, a re-evaluation of that stance has to be underway.

It’s been a brutal start to the second half for Oklahoma City, a horrible stretch that continued with Thursday night’s 121-106 loss to the Golden State Warriors in Oakland, Calif. Sure, the Thunder was playing on the second half of a back-to-back Thursday night, 24 hours after collapsing in the second half against the Los Angeles Clippers (more on that in a minute).

But that was no excuse for the way Oklahoma City allowed itself to get blown off the court over the final 16 minutes 53 seconds of Thursday night’s contest. After Serge Ibaka made a three-pointer to put the Thunder up, 80-71, with 4:53 remaining in the third quarter, the Warriors outscored Oklahoma City 50-26 the rest of the way — catching and subsequently blowing past a Thunder outfit that seemed powerless to stop it.

If that sounded familiar to anyone, it’s probably because it looked awfully similar to the way the Thunder fell apart in the fourth quarter against the Clippers. In that contest, Oklahoma City gave up a 26-5 run to end the game to allow a 22-point lead to slip away and hand Los Angeles a victory.

After that one, Kevin Durant attempted to sound the alarm. “They made plays, we didn’t,” he told reporters. “They were disciplined, we weren’t. We want to be a great team. We’re fooling ourselves. If we just want to be a great team, the way we’re playing, we’re fooling ourselves. We want to win a bunch of games in the regular season, that’s cool, but we’re fooling ourselves with the way we’re playing.”

Then the Thunder did the same thing against the Warriors.

There’s certainly no shame in losing to Golden State – the Warriors, after all, are now 55-5, and have now won 44 home games in a row dating from last season. But the Thunder looked like it wasn’t interested in finding a way back into the game over the final few minutes Thursday night.

What’s worse is the Thunder’s players allowed the game to start slipping away from them over the first four minutes of the fourth quarter, when the Warriors had their three all-stars – Stephen Curry, Klay Thompson and Draymond Green – sitting on the bench.

Once Warriors Coach Steve Kerr brought his star trio back in, Golden State methodically took Oklahoma City apart. Suddenly, the Warriors have beaten the Thunder three times in less than a month to sweep the season series.

These are bleak times for the Thunder, which had itself in position to pick up three huge victories just within the last week alone – at home against the Warriors last Saturday night, Wednesday in Los Angeles and against the Warriors again on Thursday night.

Instead, Durant and Co. turned those potentially season-changing victories into three demoralizing losses — all for different reasons. The game Saturday, of course, was decided by Curry’s stupendous three-pointer at the buzzer in overtime. But because of the unbelievable ending, people have already forgotten the fact it never should’ve happened. The Thunder was leading by four points with less than 15 seconds to play. Home or not, that’s a game the Thunder simply had to win.

But poor late-game execution by Oklahoma City allowed the Warriors to have a chance, and when they got that chance they seized it, setting up Curry’s latest forever moment. Finishing games has been a problem all season; the Thunder is tied with the lowly Philadelphia 76ers for the most games with a blown fourth quarter lead, with 10. Golden State, on the other hand, has none.

Oklahoma City’s closing problems carried over to Wednesday’s game in Los Angeles, where the Thunder dominated until they allowed the Clippers to storm back and embarrass them.

Thursday night’s game might be the most troubling of all, though. The Thunder’s first two games against the Warriors – Feb. 6 in Oakland and last Saturday’s game in Oklahoma City – came down to the final moments. But this game had the feeling that the Warriors took the Thunder’s will, to the point where it seemed the Thunder just wanted to take the loss and go home.

Since the all-star break, Oklahoma City has had four marquee games: at home against the Cleveland Cavaliers, and then these three games against the Warriors and Clippers within the last week. The Thunder has lost them all.

Suddenly, Oklahoma City is now tied in the loss column with the Clippers for third place in the Western Conference – something both teams will desperately want, if only to avoid having to play the Warriors until the Western Conference finals. That would mean playing San Antonio in the Western Conference semifinals instead (the 52-9 Spurs, remember), but anyone – including San Antonio – is a better option than the Warriors.

If things don’t start to change for Oklahoma City, however, the Thunder won’t accomplish its postseason goal, regardless of who they face come playoff time.

This was the year that things were supposed to be different in Oklahoma City. After injuries to Russell Westbrook, Ibaka and Durant sabotaged each of the past three seasons, the Thunder is healthy this season. And, after years of pinching pennies, the Thunder is paying the luxury tax to surround its stars with enough talent to finally win the championship that has eluded them.

The clock is ticking, too. Durant is set to be a free agent this summer, and even though most people expect him to re-sign with the Thunder – amid persistent rumors of his wanting to join the Warriors – those that do think he’ll sign a one-year deal with an option for a second, putting him in line to be a free agent again in 2017, when Westbrook and Ibaka’s contracts also expire.

These past two weeks, however, have only exposed this team’s flaws. The poor defense, the lack of two-way players with whom to surround their stars, the stalling out of an offense that still seems too rudimentary and reliant on Westbrook or Durant.

There’s still time to figure things out, but Oklahoma City had better do it fast. The postseason is already on the horizon, and these past two weeks have shown just how much work the Thunder has to do before it arrives.