Everyone has their favorite games within series. Game 1 of some series -- including Houston-Golden State -- can take an outsized importance. Game 5 of a 2-2 series is pivotal. After that, one team will be facing elimination, so the stakes are naturally higher.

I've always been partial to Game 4 of a 2-1 series. It determines the entire feel going forward. After 48 minutes, the series is either tied or almost decided, with very little middle ground. The tension is momentous.

We have two such Game 4s in these otherwise very boring conference finals -- starting Monday night in Cleveland. If the Cavs win, they go to Boston with the world's best player, momentum, and very rational confidence -- as opposed to the irrational brand that drives every Jordan Crawford/Clarkson one-versus-everyone prayer. Boston cannot bank on winning every home game (right?). If Boston wins, Cleveland stares again into the LeBron-might-leave abyss -- only with an even deeper deficit.

Some things to watch

• Ty Lue is riding with centers -- Tristan Thompson and the revitalized Larry Nance Jr. -- and gave both of them a clear directive in Game 3: stick with Al Horford at all times. Horford is one of the wiliest screeners in modern NBA history. He loves to slip picks before really setting them, or to veer off toward the 3-point arc. He'll sometimes meander out as if to set a screen, only to stop five feet short and force his defender to navigate a confusing situation.

In Game 3, Thompson and Nance stopped worrying about Boston's ball handlers, aside from perhaps a token pause of recognition, and tracked Horford wherever he went:

They vaporized Horford. He took four shots. A total of 19 Boston possessions ended directly via a Horford pick-and-roll, meaning one of the two participants -- or a Celtic player one pass away -- finished the trip with a shot, turnover, or drawn foul, per Second Spectrum tracking data. That player was Horford only three times. Only one of those three possessions produced a good shot.

Before Game 3, Horford had been the last Celtic to touch the ball on almost 30 percent of possessions in which one of his screens led directly to a shot, according to Second Spectrum. Editor's Picks Lowe: Behind the scenes of a tense and wacky NBA draft lottery

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The Celtics have now had a game and an off day to digest this. They will be ready. The Cavs know Boston will be ready. Some adjustments have a one-game shelf life.

Still: I suspect we will see something like this anti-Horford scheme Monday night. Boston has some obvious counters. Sticking to Horford opens up driving lanes for Terry Rozier, Marcus Smart (assuming the Cavs don't just go under screens against Smart), and other ball handlers. Rozier read this in Game 3, and zoomed untouched into the lane on a few possessions. He just failed to make plays.

Boston's guards should amp up their off-the-bounce aggression. If they have to shake only one defender on a pick-and-roll (their own), they should tilt those defenders off balance before the screen -- perhaps by faking toward it, and then darting the other way.

Horford can help them. If Thompson and Nance take away his slips and fades, Horford is under no obligation to use them. Just set some solid screens to open runways for his guards. If those guards inflict more damage, Cleveland will have to adjust -- perhaps unlocking those slips and fades again.

• One reason Boston's guards had issues making plays in traffic: There was a lot of traffic. Boston played big for much of Game 3, with either Aron Baynes, Greg Monroe, or Guerschon Yabusele alongside Horford (Yabusele somewhat inexplicably so). Horford and Baynes logged 12 minutes together in Game 3, their highest figure in the series. Boston is minus-3 in 28 minutes those two have shared the floor against Cleveland, and minus-24 in 150 such minutes over the postseason, per NBA.com. Kevin Love, guarding those centers, did a nice job contesting shots at the rim.

Boston has been much better with Horford at center. Brad Stevens doesn't have a ton of options. With Shane Larkin injured, Boston is down to five trust-him-every-game perimeter-ish players around Horford: Rozier, Smart, Jaylen Brown, Jayson Tatum, and Marcus Morris. Even Mike D'Antoni (probably) wouldn't play just a six-man rotation. The centers have to play some. (This depth issue may work toward Stevens starting Baynes despite all those numbers. He has to play, and it might be easier to just play him when you know Thompson is going to be on the floor for extended stretches. Then again, the Cavs playing Nance -- and rarely going to Love at center -- mitigates that a bit. Cleveland could always go back to Love-at-center immediately when Horford rests as a way of targeting Baynes -- something I suggested last week.)

Two of those five players -- Morris and Smart -- are minus 3-point shooters. Boston has been successful playing them together in smaller groups with Horford at center, but the scoring efficiency of such lineups has dipped a ton in the playoffs -- when defenses take an extra step away from bad shooters. (Kyrie Irving's injury hurts, too.) Play those two with a center, and the offense is in mud.

Stevens should chance more time with Horford at center, and shift perhaps all of the Monroe/Yabusele minutes to Semi Ojeleye, who can at least hit a wide-open corner 3 and absorb some of the LeBron assignment on defense. (You don't defend LeBron. You just absorb time trying to.)

• Cleveland also switched whenever possible on Horford pick-and-rolls, often by slotting bigger defenders -- Jeff Green, LeBron -- onto Smart. (I wonder if we might see more of LeBron on Rozier as the series progresses.) You could see Horford digesting that, and searching out responses.

Nance and Green switch Horford's pindown for Smart, and then re-switch when Horford screens for Smart up top. Horford knows that second switch is coming. He knows that Nance, about to switch onto him, expects him to roll to the rim. He counters with a delayed fade that completely fools Nance. Problem: LeBron sees that, zooms over like Mario after nabbing a Starman, and annihilates Horford.

If you are going to make that rotation off of Tatum, you'd better make it hard -- and with serious airtime to disrupt that swing pass. LeBron's defensive energy was on another level in Game 3, and it needs to stay there. When he treats Brown as a dangerous shooter, and closes on him fast, he erases Brown's best looks. When he half-asses it, Brown feasts.

• When LeBron is on Smart, a smaller Cavs defender -- JR Smith or Kyle Korver -- is often stashed on Morris. Boston might want to poke at that matchup. Morris' bully-ball represents boring, retrograde hoops, but when he has a mismatch, it might be the best way to use him.

• Of course, Cleveland playing non-shooting centers makes it harder for its own offense, too. A big part of Game 3 was Cleveland finally finding ways to hurt Boston's centers on the pick-and-roll.

Part of it was LeBron being a genius -- fooling Boston defenders by twitching toward picks before bolting the other way, crossing fools over, throwing haymaker passes precisely zero other NBA players can pull off.

Cleveland also selectively pushed the pace, even after Boston makes. Catch a defense backpedaling, and you don't have to do anything fancy to beat it. Moving fast also made it harder for Horford to find Love on defense, since Love is rarely guarding Horford on the other end. For the first time, Love got a few easy looks because Boston couldn't get to its optimal defensive assignments.

Part of it was smart tactics. Cleveland often had Thompson and Nance set an off-ball pick on their way up to LeBron. That first pick was a diversion -- a trick to make Boston's centers pause in the paint, so that LeBron had more room to work up top. Watch Nance slam Tatum near the foul line:

That doesn't look like much, but Baynes hanging back an extra few feet to patrol Tatum's man warps the geometry of the play. LeBron can slice in deeper, Nance has more room to dive, and everyone has to rotate further -- including Yabusele off of Love.

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The same action preceded Nance's lob dunk in the fourth quarter; look how far Nance's man (Monroe) is from LeBron as Nance sets his pick:

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LeBron drove hard to his right, drew Monroe further off of Nance than Monroe wanted, and lofted that bad boy. (By the way: Look at Brown in Korver's jersey in the left corner. Brown is technically the emergency weakside helper. He is not leaving Korver.)

Even when those off-ball picks don't connect, they throw defenses off-kilter. Big men fall so far behind, it is hard for them to call out the ball screen in time; LeBron's defenders looked unaware and jittery when they felt a pick.

• On a more basic level, the Cavs ran more of the profitable two-man actions that had been staring them in the face since before the series started. George Hill and LeBron screened for each other off the ball -- what a concept! -- forcing the Celtics into a choice: switch Rozier onto LeBron, or stay home and risk someone popping open. When Boston stayed home, the Cavs jaunted into dunks and open 3s. When the Celtics switched, LeBron went to work.

Boston has done well against the Hill-LeBron two-man game, but Cleveland hasn't used it enough. For the playoffs, the Cavs have scored 1.14 points per possession when Hill screens for LeBron, and 1.17 the other way around -- elite marks, per Second Spectrum.

• It can even work with Clarkson! After Horford sank a jumper early in the second quarter, LeBron rushed up the left sideline, took a screen from Clarkson with about 20 on the shot clock, earned a switch, posted up Rozier, drew help from Horford, and nearly found Nance for another alley-oop:

Brown busted that by abandoning Korver in the corner, but coaxing that crisis rotation is a win for the Cavs. LeBron, Nance, and Thompson were all more attuned to short-range lob possibilities.

Forcing point guards onto LeBron is always good. It draws every eyeball. Remember when Thompson sprung Smith for an open triple with a nasty flare screen? It happened because literally every player on the court -- including Smith's man -- stared at James lording over Rozier:

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• Also good and underutilized until Game 3: the Hill-Love two-man game.

Cleveland in the playoffs has scored 1.31 points per possession on any trip featuring a Love screen for Hill, a number that would have led all duos in the regular season, per Second Spectrum. Love has set just 23 such screens in this series -- not enough.

If Boston stays home, Love pops open from deep. Switch, and Love works a mismatch -- as he did in beasting on the play above. That play is instructive: Smart is on Thompson, and Boston is right to ride with wings guarding Thompson so that Horford can stay on Love. The Cavs haven't punished that mismatch on the glass; they grabbed only 16 offensive rebounds combined in Games 2 and 3.

But you see one damaging ripple effect: Smart is the closest player available to rescue Rozier from guarding Love. Normally, the player defending Thompson would be a center well-equipped to do that. Smart is not a center. He is stout enough to withstand some Love post-ups, but Love shows here that when he gets mean, he can dislodge Smart. If he keeps doing that, Boston might send help.

• One potential Boston solution: Have Rozier guard Smith instead of Hill, so that a bigger, more switchable player defends Hill. Of course, Cleveland can shift more of the two-man stuff toward Smith. Even so: That shift is probably a win for Boston.

• Even the Hill-Thompson combination worked. It really shouldn't, since the Celtics can switch everything when they have a smaller player -- Smart, Morris, Brown -- defending Thompson. But it's still worth trying:

This play is everything for Cleveland. Rozier switches onto Thompson. Boston should be fine with that. Brown panics, and tags out Rozier. Problem: That leaves Rozier on LeBron.

LeBron too often has checked out when other Cavs run the offense. As Brian Windhorst has written, he is resting on the court. Some such rest is unavoidable. The burden on LeBron is too big. (Related: Irving plays for Boston, and Thomas just had hip surgery.) But for Cleveland to have a chance, he has to cut those resting possessions by something like half. Perhaps shifting more off-the-bounce duty to Hill kept LeBron's tank full.

Maybe Boston expected him to chill here. In real time, I did, too. After all, there are only seven ticks left on the shot clock when Rozier arrives on LeBron.

Instead, LeBron shifts into predatory mode. He drags Rozier into the Dirk spot, draws help, and creates an easy triple for Love.

This is the LeBron Cleveland needs. This is the sort of offense they need. If they get it, the Cavs can set the stage for one of those pivotal Game 5s in one of LeBron's favorite road arenas.