Former Philadelphia 76ers coach Brett Brown had a unique rotation, in which he would have at least two of his starters on the floor for the entire game (not counting garbage time). To stagger their minutes like that, Brown had to minimize the minutes that all five starters were all on the floor. Much was made about the “fit” of the Sixers’ starting lineup last season, but that lineup averaged just 10.7 minutes per game.

New Sixers coach Doc Rivers changed the script this season, staggering his starters’ minutes just a minimal amount and consistently using a second unit comprised of five reserves. This year’s lineup (with Seth Curry and Danny Green in place of Josh Richardson and Al Horford) averaged 20.5 minutes per game, the most among 346 league-wide lineups that played in at least 10 games together and almost twice as many as last season’s group.

It was hard to argue with the results. Through the first round of these playoffs, the Sixers were 27-5 when they had their full starting lineup, with one of those five losses being Game 4 in Washington, when Joel Embiid didn’t play after the first quarter, having suffered a right knee injury. Another was a February loss in Tampa when the starting lineup was a +21 in its 15.4 minutes and the Sixers were outscored by 28 points in 32.6 minutes with at least one reserve on the floor.

Rivers used a full-reserve lineup at times in the first round, and it was back for Game 1 of the Eastern Conference semifinals on Sunday. And while there were many factors contributing to the Sixers’ 128-124 loss to the Atlanta Hawks, the minutes for that second unit were brutal and helped put the Sixers in a hole that they just couldn’t climb out of.

Eight possessions can make a difference

The Sixers were already down 11 points when Furkan Korkmaz replaced Curry with 43 seconds left in the first quarter, joining George Hill, Tyrese Maxey, Matisse Thybulle and Dwight Howard on the second unit. And prior to Sunday, Philly was just 9-20 after trailing by double-digits this season. As volatile as in-game swings can be with the pace and 3-point shooting of today’s NBA, no team is better than 12-15 after trailing by 10 points or more.

Still, an 11-point deficit is much more manageable than a 20-point deficit, which is what the Sixers had by the time Tobias Harris replaced Thybulle with 10:06 remaining in the second quarter. Prior to Sunday, they actually had the league’s fifth-best record when trailing by 20 points or more, but that record was 1-10, with the one win having come in Indiana in late January.

The five-man second-unit stretch lasted only 2:37, eight offensive possessions and seven defensive possessions. And at the start of it, the Hawks had five reserves on the floor themselves.

Rough shooting/spacing

Some of that second unit’s issues came from bad mental mistakes. Maxey gambled for a steal and clumsily fouled Danilo Gallinari in the backcourt with the Hawks in the bonus. Howard threw an outlet pass to Thybulle, who wasn’t expecting it.

There were a couple of simple, physical mistakes. Hill threw a baseline pass out of bounds, while Maxey stepped out in an attempt to get a shot off at the end of the first quarter.

But some were about the construction of that second unit, which has only two capable shooters – Hill and Korkmaz – among its four perimeter players. The play the Sixers ran to start the second quarter had Korkmaz curling to the top of the key off two screens. But when he wasn’t able to get a clean look, it was Thybulle (instead of Hill) as the weak-side spacer. He missed a 3 from the left corner, from where he has now shot 8-for-41 (20%) this season (8-for-38 in the regular season, 0-for-3 in the playoffs)…

Two possessions later, a Maxey/Howard pick-and-roll brought two defenders to the ball. That should have resulted in a four-on-three situation and an open shot for the Sixers. But the spacing allowed the Hawks to recover and reset…

The Sixers’ five-man bench unit went scoreless on its eight offensive possessions, turning the ball over five times.

A defensive mistake

It also allowed nine points on seven defensive possessions. Two of those came on Gallinari’s free throws after Maxey’s clumsy foul. Another two came from Williams snaking into space against Howard’s pick-and-roll coverage. And the final two came when Onyeka Okongwu stripped Howard in the high post and ran out on the break.

But Thybulle and Hill, two very good defenders, gave the Hawks another opening when they botched a switch. On a sideline out-of-bounds play that half the league runs, Williams set a back-screen for Gallinari (the inbounder). Hill switched onto Gallinari, but Thybulle stayed with him. When he tried to recover to Williams, the vet just side-stepped him into an open corner 3…

After Rivers started bringing back his starters, the Atlanta lead ballooned to 26 points. The Sixers climbed all the way back to within three in the final minute of the fourth quarter, but never had a chance to tie or take the lead. In total, the Sixers’ starting lineup was a +14 in its 27.3 minutes on Sunday, scoring 83 points on 63 offensive possessions (1.32 per). Philly was outscored by 18 points in 20.7 minutes otherwise, scoring just 41 points on 43 possessions (0.95 per).

Entering Game 1, the Sixers’ primary concern was the health of Embiid, because he’s their MVP and because they haven’t been very good when he hasn’t been on the floor. Embiid looked pretty darn good, scoring 39 points (on 12-for-21 from the field and 14-for-15 from the line) in his 38 minutes. But the Sixers were really bad when he wasn’t on the floor.

It was shades of the 2019 Eastern Conference semifinals, when the Sixers were amazingly outscored by 109 points in 99 minutes with Embiid off the floor and lost at the buzzer in Game 7.

Three more numbers to know

• Game 1 was, by far, a much faster-paced game (108 possessions for Atlanta, 106 for Philadelphia) than any that the Hawks played in the first round against New York.

• The Sixers allowed just 180 corner 3s (2.5 per game) in the regular season, tied for the second fewest in the league. The Hawks were 8-for-17 from the corners on Sunday, with the eight makes being tied for the second most and the 17 attempts being the most against Philly this season. The Sixers were just 1-for-4 from the corners.

• According to Second Spectrum tracking, the Hawks set 66 ball screens for Trae Young and scored 1.33 points per chance when they did. That was up from 1.12 points per chance (on 44 ball screens per game) in the first round.

Up next: Game 2

Rivers went away from the full bench unit after those fateful 2:37 on Sunday, though all five guys (plus Shake Milton) played in the second half. We can expect more staggering in Game 2 on Tuesday (7:30 p.m. ET, TNT), which would reduce the time that all five starters are on the floor together. We can also expect more of Ben Simmons guarding Young, who had 25 points (on 5-for-7 shooting), seven assists and one turnover (with Green as his primary defender) in the first half of Game 1, but 10 points (on 3-for-10), three assists, and three turnovers (with Simmons guarding him some) in the second half.

Game 1 was the first loss all season that the Sixers suffered at home (they were previously 18-0) with their full starting lineup available. Before they can think about regaining home-court advantage, they have to make sure they don’t suffer another.

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John Schuhmann is a senior stats analyst for NBA.com. You can e-mail him here, find his archive here and follow him on Twitter.

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