Maybe the Bucks would have won Game 4 if superstar Giannis Antetokounmpo hadn’t been injured. That’s unknowable. What’s known is that the Bucks were caught flat-footed by a Hawks blitz they should have seen coming. That’s inexcusable for a team with championship aspirations and, worst for the Bucks, it wasn’t a shock.

Falling short of expectations has become the norm for the Bucks with coach Mike Budenholzer. He once helped lift the underdog Hawks to unprecedented heights as coach, and thus was given control of their basketball operations. Budenholzer left after Year 1 of the Hawks’ rebuild for Milwaukee, where his team keeps falling on its face as front-runners.

Trae Young sat out Tuesday with a right foot injury. The Hawks still blew out the Bucks at State Farm Arena to tie the best-of-seven Eastern Conference finals 2-2. Antetokounmpo is listed as doubtful for Game 5 on Thursday in Milwaukee after the Bucks said he suffered a hyperextended left knee.

If Antetokounmpo can’t play again in this series, I doubt Bucks backers will be understanding of Budenholzer’s predicament. Not after what happened in Game 4 and the two postseasons previous. The Bucks failed to make the NBA Finals the past two years with league MVP Antetokounmpo. Budenholzer seemed on his way to redemption this postseason when the Bucks swept the Heat, outlasted the Nets and took a 2-1 series lead against the Hawks.

Surely, Coach Bud’s guys would take care of business with Young in street clothes.

They didn’t. The Hawks, energized by a home crowd that still believed, buried the Bucks from the start.

“We thought we were just going to walk in and win this game,” Bucks forward P.J. Tucker said.

How could these Bucks ever think that? They were beaten favorites in the past two postseasons. The Bucks should have noticed how many times the Hawks seemed finished against Philadelphia in the semifinals yet never, ever gave in. There was no way the Hawks wouldn’t give their best shot.

They did, and the Bucks weren’t ready.

“They came out with that desperation, the desperation they didn’t want to go down 3-1,” Bucks guard Jrue Holliday said. “And we didn’t have that fight.”

Hawks forwards Danilo Gallinari (left) and Onyeka Okongwu double team Milwaukee Bucks center Brook Lopez.   “Curtis Compton / Curtis.Compton@ajc.com”

Credit: Curtis Compton / Curtis.Compton@

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Credit: Curtis Compton / Curtis.Compton@

The Bucks were favored by 6½ points hours before Game 4. The betting line started to climb when word came that Young would sit, and it was 9 points at tipoff. According to ESPN Stats and Info, Milwaukee’s loss is the second-biggest upset in the conference finals over the past 30 years. The 2017 Cavs lost to the Celtics as 16½-point favorites, and the 2003 Spurs lost to the Mavericks as nine-point favorites.

Both of those teams recovered. The 2003 Spurs went on to win the NBA championship. They were coached by Gregg Popovich, with Budenholzer on his staff as an assistant. The 2017 Cavs, coached by Tyronn Lue, won the conference finals before losing in the championship round to the Warriors.

Budenholzer doesn’t inspire nearly as much confidence as his old boss Popovich, a coaching legend. Lue is proving wrong the perception that he was just along for the ride with LeBron James. Kawhi Leonard, his best player, hasn’t played the past six games. The Clippers still closed out the top-seeded Jazz in the semifinals and rallied from 2-0 down in the West finals Monday night to force a Game 6 late Wednesday night.

Meanwhile, Budenholzer’s Bucks are again scuffling to win a series they are heavy favorites to win. The injury to Antetokounmpo came after the Bucks didn’t look prepared for Game 4. That compounded some questionable strategic decisions by Budenholzer earlier in the series.

The Bucks lost Game 1 to the Hawks while playing a defensive scheme that gave Young room to roam through the lane. When the Bucks had a chance to tie the score at the end, Budenholzer drew up a play for Khris Middleton, who’d missed all eight of his 3-point tries. He also missed the ninth one.

Milwaukee smashed the Hawks in Game 2, then pulled away to win Game 3 after Young’s injury. The Bucks made hay with small lineups in both games, which allowed them to switch on defense. Budenholzer still has leaned heavily on alignments with slow-footed center Brook Lopez.

On the other bench, Hawks interim coach Nate McMillan squeezed every ounce of performance from his players in Game 4. They had their most efficient offensive game of the postseason since Game 4 of the Knicks series. I wondered where the Hawks would get points from with their best scorer sidelined. Answer: everywhere.

The Hawks transformed their attack from Young making things happen on pick-and-rolls, to everyone quickly moving the ball until someone had a good shot. Old pro Lou Williams took Young’s place in the lineup and went for 21 points and eight assists. Bogdan Bogdanovic (20 points) finally rediscovered his shooting stroke. Four other Hawks scored 10 points or more, and five players had at least two assists.

And the Hawks dug in on defense, which has been a constant this postseason. That’s McMillan’s influence. He waited to give Cam Reddish meaningful minutes after Reddish sat out four months because of injury. The patience paid off when Reddish, a defensive ace, helped hold Middleton to 16 points in Game 4 after he scored 38 in Game 3.

The Hawks were wobbling when Antetokounmpo went down. He’d scored eight points in less than five minutes of the third quarter while making all four of his shot attempts. Milwaukee’s 13-point halftime deficit got down to seven. It was 10 points when Antetokounmpo’s knee buckled when he landed awkwardly after an unsuccessful challenge of Clint Capela’s alley-oop dunk.

Middleton scored to cut Milwaukee’s deficit to eight points. The Hawks ran off 15 consecutive points to essentially finish off the Bucks.

Budenholzer: “Overall, either before the injury or after the injury, credit Atlanta for how they played.”

The Hawks deserve the accolades. Their best player was out, so they created a synergy that overwhelmed the Bucks. They were intense and focused from buzzer to buzzer. The Hawks need to two more victories to reach the NBA finals for the first time since the NBA-ABA merger in 1976, and the first overall since 1961. If Young can’t play, they have proof that they can beat the Bucks without him.

Maybe that wouldn’t have happened if Antetokounmpo didn’t get hurt. There’s no way to know that. What’s certain is that the tough-minded Hawks have given Coach Bud’s Bucks reason to think about blowing it again.