The scenario is simple right now for Milwaukee and Golden State: Win a road game Monday night, go home toting a 3-1 series lead and be one win from a spot in the NBA’s version of the Final Four.

The scenario is equally simple for Boston and Houston: Win a home game Monday night, or else.

Top-seeded Milwaukee leads fourth-seeded Boston 2-1 in their Eastern Conference semifinal series, and top-seeded Golden State leads fourth-seeded Houston 2-1 in their Western Conference semifinal. The Celtics and the Rockets host Game 4s, knowing a win will earn them a berth in what becomes a best-of-three showdown and knowing a loss places them squarely on the abyss that overlooks elimination.

“It’s a great opportunity to respond,” Celtics Coach Brad Stevens said.

Boston had the home-court edge over Milwaukee, then gave it back with a loss Friday night. Houston was a bounce or two away from getting into the most-dreaded 3-0 hole against Golden State, then rallied to win Game 3 on Saturday night and keep realistic hope alive against the two-time defending NBA champion.

“Every game is a must win for us and we have to play like that,” said P.J. Tucker of Houston, who made a slew of key effort plays to help the Rockets survive Game 3. “Every single possession we have to fight for the ball, fight for everything the entire game.”

The Celtics and Warriors are going to look for more from their star guards in Game 4.

Kyrie Irving of Boston was 8 of 22 from the floor in the Celtics’ Game 3 loss. Stephen Curry of Golden State – playing with fingers taped together on his left hand following a dislocation of his middle finger – was 7 of 23 in the Warriors’ Game 3 loss, and was almost universally mocked on social media after missing a dunk in the final seconds.

“I want to shoot the ball better and that’s going to happen,” Curry said.

A big boost for Boston could come from Marcus Smart, who hasn’t played in a month and has yet to appear in these playoffs after a left oblique tear. Smart practiced on Sunday and has been cleared for contact, though no determination for his Game 4 availability has been officially made.

“I’m close,” Smart said Sunday.

“He’s close,” Stevens said.

That would seem like a strong hint.

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