Updated

March Madness is history, and the too-long NBA regular season is mercifully over. But now comes the true test of champions -- the NBA playoffs.

And despite the Lakers' standing as the reigning champs, just about each of the opening series is up for grabs in the West.

LAKERS (1) VS. THUNDER (8)

Why the Lakers should win.

OKC has nobody in the middle who can make Pau Gasol exert himself on defense. Plus neither Nenad Krstic nor Nick Collison has the defensive chops to seriously challenge Gasol. Serge Ibaka has the power but not the experience, while little-used Etan Thomas has the experience but will need a road map to find his way up and down the court.

Similarly, Jeff Green can't keep up with Lamar Odom's quick-footed lefty slashes and sure-handed rebounding.

If Andrew Bynum returns, then the Lakers will be deeper than the Thunder, and Green will be forced to contend with Gasol.

Kevin Durant will be bullied from baseline to baseline by Ron Artest. If Ron-Ron has trouble navigating high screen/rolls, the Lakers can always double Durant and force a lesser player to try to beat them. And the young Thunder will all be surprised by the physical play that characterizes playoff competition.

Every single play is intensely pressurized so the concentration levels must be stepped up, and the young challengers will make too many mistakes.

After cruising through the last few weeks, the Lakers will quickly get their stuff together.

There's no substitute for championship experience (both on the court and on the bench), and for the confidence inherent in champions.

Moreover, Kobe simply won't let the Lakers lose.

Why the Thunder could win.

Thabo Sefolosha defends Kobe as well as anybody.

Russell Westbrook will run rings around Derek Fisher, forcing the mistake-prone Jordan Farmar and Shannon Brown to log too many minutes. Also, Westbrook's quicksilver ventures into the paint will put enormous pressure on L.A.'s bigs to make timely rotations and protect the rim.

Durant is quite capable of running away from Artest and lighting up the Lakers for 30-40 points.

Even though they're strangers in paradise, the Thunder really have nothing to lose and can afford to play loosey-goosey. Plus, they're too young to be afraid of the big, bad Lakers.

OKC could conceivably steal a game or two while the Lakers get themselves in gear -- and then anything would be possible.

MAVERICKS (2) VS. SPURS (7)

Why Dallas should win.

Dirk Nowitzki presents a huge matchup problem for the Spurs. Richard Jefferson is too small, Antonio McDyess is too old and immobile, Matt Bonner is too slow, and Tim Duncan would be far removed from his comfort zone if Nowitzki received the ball in the neighborhood of the 3-point line.

Caron Butler is a solid 2-way player, who will give either Jefferson or Manu Ginobili fits.

Jason Kidd has always been a masterful organizer and has recently developed a dead-eye 3-point shot. He's big and strong enough to abuse either Tony Parker or George Hill in the low post.

In Erick Dampier and Brendan Haywood, the Mavs have a pair of defense-minded bangers in the middle. They can abuse McDyess and Bonner and have Tim Duncan aching and gasping for breath by the fourth quarter.

Shawn Marion has lost a step, but has at long last accepted being a role player. As such, he can fill in the empty spaces at both ends of the court and make a significant difference in close ball games.

With Jason Terry and J.J. Barea, Dallas can bring explosive scorers off the bench.

The Mavs have too much firepower and too much mass at the center spot.

Why San Antonio could win.

Ginobili is healthy and his on-target jumpers set up his drives. He also has the quickest last step in the league and cannot be adequately defended by any one of the Mavs -- except perhaps J-Kidd.

If Tim Duncan can hit his overrated off-the-glass jumpers with any degree of regularity, he'll force Dampier/Haywood to come out and play defense in no-man's land.

Parker can zip past anybody the Mavs front him with -- and if his jumpers are also falling, SA's offense becomes extremely versatile.

Jefferson has the capability of recapturing the rapture of his salad days with the Nets -- running, pulling-and-popping, executing tricky drives, and playing ace defense.

Hill has become a vastly underrated performer, who can do just about anything that Pop asks of him.

McDyess is an old warhorse who can still plug mid-range jumpers.

Bonner's long-range marksmanship can spread the floor and give TD room to operate in the low post.

If they can hit their perimeter shots and make precise defensive rotations, the Spurs will be tough to beat.

Meanwhile, Nowitzki and Terry have yet to prove that they can rise to the occasion in tightly-fought playoff games against high-quality opponents.

Most importantly, the clutch play of Duncan and Ginobili should never be underestimated.

Despite the vast difference in the respective seeds of these two teams, this should be an extremely combative and fascinating series.

SUNS (3) VS. TRAIL BLAZERS (6)

Why Phoenix should win.

On offense, Steve Nash and Amar'e Stoudemire are as perfectly coordinated as Siamese twins. Nash's crafty handling coupled with Stoudemire's resurrected quickness is a potent combination that Portland simply cannot contain.

Especially since Andre Miller, Rudy Fernandez, Jerryd Bayless and (especially) Juwan Howard are all deficient defenders. For sure, Marcus Camby can run and jump with Stoudemire, but Portland's center is also strictly a finesse player who tends to pick up early fouls.

Because Stoudemire and Little Stevie Wonder are playing at the tops of their respective games, the Blazers defense absolutely must concentrate on jamming them -- which will inevitably eventuate in uncontested treys for Channing Frye, Jason Richardson, Jared Dudley and Goran Dragic.

With Brandon Roy hobbled by a torn-up knee, the Blazers will be unable to run with the Suns, or have a reliable go-to scorer.

Why Portland could win.

If Roy, Greg Oden, and Joel Przybilla (and Sam Bowie?) all experience a common and miraculous healing.

Otherwise, the Trail Blazers are destined to lose their way in the southwestern desert.

NUGGETS (4) VS. JAZZ (5)

Why Denver should win.

Because their players are more athletic and more talented.

Because Carmelo Anthony is too strong for Andrei Kirilenko to subdue.

Because J.R. Smith is a dynamic point-maker who can only be limited by his own foolish decisions.

Because Chauncey Billups can still hit game-clinchers and game-winners on a routine basis.

Because Nene is a strong man and Chris Andersen in a maniacal defender and rebounder.

Because Kenyon Martin is a bully in his own backyard.

And because Carlos Boozer may be extremely hampered by a strained oblique muscle that will cause severe pain every time he lifts his right arm.

Why Utah could win.

Their perpetual-motion, precision offense will generate easy shots against Denver's soft-hearted defense.

Deron Williams is still approaching his peak, while Billups is just about past his.

Mehmet Okur's outside shooting will frustrate K-Mart, who is only effective playing defense in the shadow of the basket.

AK-47's length, quickness, and defensive instincts should not be overlooked. He could conceivably force Melo into taking bad shots and making unwise passes.

If Boozer is healthy, he has too much stuff to be bothered by the defensive efforts of either Nene or Andersen.

C.J. Miles is the wild card in Utah's offense. If his shot is hot then Denver's already thin defense will be forced to stretch to the breaking point.

Denver's iso-offense is extremely predictable.

Finally, the Jazz players have the discipline and the character to relentlessly grind away from the opening tip to the final buzzer, thereby frustrating the emotionally unstable Nuggets.

This shapes up to be still another intriguing series.

If you have a question or comment for Charley Rosen, please email charleyrosen@gmail.com and he may respond in a future column.