It was a busy weekend for world-class fighters as two RING world champions and a number of RING-rated contenders were in action.

The best performance was turned in by world lightweight champion Juan Manuel Marquez, who successfully defended his 135-pound crown against No. 1 contender Juan Diaz with a breathtaking ninth-round knockout in an early fight-of-the-year candidate. However, world cruiserweight champ Tomasz Adamek, who turned back the challenge of undefeated Johnathon Banks, wasn’t too shabby.

The two veterans overcame early points deficits against their motivated young challengers and personified the definition of the word “champion.” Marquez (50-4-1, 37 knockouts) and Adamek (37-1, 25 KOs) represented THE RING titles with honor and furthered their claims as the best fighters in their divisions.

“It was marvelous to see two RING magazine champions perform so well in exciting title fights over the weekend, fought in front of large, enthusiastic crowds,” said Nigel Collins, editor of the magazine. “It’s amazing how well boxing is doing in these difficult financial times, which reinforces THE RING’s philosophy of allowing the marketplace to make the fights, as opposed to sanctioning organizations forcing mandatory defenses down the fighters and the fans’ throats.

“Giving the paying public what they want has always been the best business model, and it’s gratifying to see boxing returning to this time-honored formula for success.”

Also in action, in the co-featured bout to Marquez-Diaz, was THE RING’s No. 1 featherweight contender, Chris John, who retained his WBA title after a rousing (and rare) unanimous draw with Rocky Juarez.

The 12-round bout with John (42-0-2, 22 KOs) was the fourth title shot for Juarez (28-4, 20 KOs) and only his second fight at featherweight dating back to May of 2006, when he first stepped up to the junior lightweight division to challenge then-130-pound titleholder Marco Antonio Barrera.

Juarez looked strong in that first bout with Barrera, which many observers thought could have been a draw or a close points win for him. However, he was easily out-boxed in their rematch and dominated again by another future hall of famer, Marquez, in a third shot at a 130-pound title.

Although Juarez fell short of winning a title again against the marvelously talented John, he looked sharper and was more active than fans have seen him since the first Barrera fight. Perhaps featherweight, the division the 2000 Olympic silver medalist campaigned in as an amateur and for most of his pro career, is where Juarez belongs.

The division, once home to the likes of Marquez and Manny Pacquiao, could certainly use Juarez’s name recognition. And there are potential 126-pound matchups against titleholders that the squat Houston native might actually win.

As physically strong, heavy handed and willful Juarez is, his slow feet, methodical style and short stature (5-foot-5) was always going to be a liability against world-class junior lightweights with superior height and reach.

The recent addition of Robert Guerrero and Jorge Linares, young former featherweight titlists who are just as tall, rangy and skilled as John but have more speed and punching power, to the 130-pound division did not bode well for Juarez.

Hopefully, Juarez stays at featherweight.

That's where he’s ranked after Saturday’s splendid fight with John. His move from the 130-pound division to 126-pound weight class caused a shake up in THE RING’s junior lightweight and featherweight ratings.

Although more than a few observers believed that John outboxed and outworked his heavier-punching foe in enough rounds to deserve a victory, Juarez’s strong showing and late rounds rally moved him from No. 3 at junior lightweight to No. 4 at featherweight.

John remained THE RING’s No. 1 contender at 126 pounds.

Juarez’ switch boosted up all junior lightweights rated below him last week one rung each and made room for Guerrero, who is in action this Saturday, to enter at No. 10.

In the featherweight rankings, everybody rated No. 4 or below last week slipped down one notch each. UK-based Mongolian veteran Choi Tseveenpurev (No. 10 last week) exits.

Here’s a brief look at what happened in the other weight classes:

CRUISERWEIGHT

Adamek made his first successful defense of THE RING magazine cruiserweight championship, scoring an eighth-round knockout of Banks (20-1, 14 KOs), who wasn’t ranked going into Friday’s title shot and remains so. However, at 26, the Detroit native has plenty of time to rebound from his first loss and eventually break into the rankings.

Canadian southpaw Troy Ross is living proof that a fighter can not only comeback from a loss but climb to heights far beyond where he was before he suffered the setback. Ross (21-1, 15 KOs), coming off four consecutive victories, including a fourth-round TKO of Ehinmen Ehikhamenor to win “The Contender Season Four” championship, enters at No. 9, replacing B.J. Flores.

LIGHT HEAVYWEIGHT

Former champ and No. 3 contender Glen Johnson (49-12-2, 33 KOs) stayed busy with an easy 10-round decision over Daniel Judah on Friday. It was Johnson’s second consecutive victory since he dropped a competitive 12-round decision to No. 1 contender Chad Dawson.

LIGHTWEIGHT

Marquez, THE RING magazine lightweight champion, retained the title with a spectacular ninth-round knockout of Diaz, who entered the bout as the No. 1 contender. Diaz’s strong showing, coupled with a relatively weak field below, allowed him to retain his previous rating.

FLYWEIGHT

Former junior flyweight champ Hugo Cazares, currently THE RING’s No. 9 contender at 112 pounds, had a stay-busy win this weekend, a third-round knockout of journeyman Jorge Romero.

Here’s the kicker: Cazares (27-5-1, 20 KOs), known for his size and power at flyweight, fought at junior lightweight.

So where should he be ranked if he continues to fight and win at weights so far above flyweight? His next scheduled fight is against former 108-pound titlist Roberto Vasquez in the 115-pound division. Sounds like a very good matchup. Win or lose, let’s hope he fights no heavier than junior bantamweight.

If Juarez couldn’t make it as a junior lightweight, there wasn’t much hope for Cazares.

Amazingly, the win was at junior lightweight, so he’ll probably be moving out of the 112 division, but we want to check with his people before making a move.