Electric play from the Oklahoma City Thunder’s transcendent young stars had a global audience transfixed. Led by their young All-Star trio of Kevin Durant (the NBA’s three-time scoring champ), James Harden (the NBA’s Sixth Man of the Year) and Russell Westbrook (finished seventh in MVP voting), the Thunder registered a 110.1 offensive efficiency heading into the Finals, easily ranking as the top offense in the postseason and even rivaling some of the best postseason offense in recent NBA history. They were young, they were bold and they were unstoppable.

They barreled through the West, eliminating three out of the last four league titleholders in the San Antonio Spurs, Los Angeles Lakers and the Dallas Mavericks. Impressive no doubt, but now that we’re three games into the NBA Finals, the once mesmerizing Thunder have appeared pedestrian against a Miami Heat squad that’s far superior on defense and way more experienced in pressured situations.

A big question heading into the Finals was how Oklahoma City would fare once it faced a team that prides itself on defense. After three games, the answer to said question is rather simple: not too good. After scoring 105 points –in what LeBron James and Dwyane Wade termed as “a feel-out game”– the Thunder dropped to 96 points in Game 2 and 85 in Game 3. Much will be made of the lineup OKC head coach Scott Brooks had on the court in the third quarter, when Durant was forced to sit with four fouls and Westbrook was given a timeout to “calm him down.” But Brooks is not to blame for the Thunder’s loss on Sunday. Poor execution, excessive turnovers, missed free throws and silly fouls, coupled with the Heat’s stalwart defense, is what did OKC in. According to ESPN Stats and Information, the Thunder converted fewer than half of their layups and dunks Sunday night, shooting 13-for-27 at the rim. “You’ve got to give them a lot of credit,” Brooks said after Game 3. “They get into you and they make you work for every shot. They’re a good defensive team.”

The Heat are playing with a greater sense of urgency. Perhaps it’s because they’re still suffering from their defeat to the Mavericks in last year’s Finals. After being served in Game 1, in which the Thunder tallied 24 fast-break points to the Heat’s mere four, Miami has seized control of the Finals and have the Thunder’s young gun trio back on their heels. Miami has forced OKC to play at a pace they’re not accustomed to, making them look uncharacteristically hesitant and intimidated around the basket. Since Game 1, the Thunder have totaled just 23 points on fast breaks combined in the past two games and the Heat have converted the Thunder’s 25 turnovers into 29 fast-break points over Games 2 and 3. Miami is winning the Big Three battle thanks in part to their swarming defense that has stymied the Thunder.

If Durant and OKC are hungry for a championship, James and the Heat are starving. Miami is a different team from a year ago. LeBron James is a different player. After scoring just 18 points in the fourth quarter of a combined six games in the Finals last season, James already has scored 21 points in three final frames this time around. He’s more determined, more aggressive and more impactful than he’s ever been. He turned in another stellar performance in the Heat’s 91-85 victory on Sunday. James finished with 29 points and 14 rebounds to give Miami a 2-1 series lead.

When the NBA Finals are tied 1-1, the winner of Game 3 usually goes on to capture the title 85 percent of the time. With the odds on their side, will the Heat prevail? Or will the Thunder get their juvenile act together to even the series on Tuesday?