In 2000, having two straight wins over Jorge Paez and Steve Quinonez, Castillo challenged WBC lightweight titleholder and Ring No.

Instead, Castillo scored the Ring Magazine Upset of the Year, defeating Johnston by a majority decision, in what was a very close fight.

[1] After fighting Johnston, Castillo defended his title against Ring Top 10 Lightweight, César Bazán.

Castillo had great success in the middle rounds, when he cut off the ring and used his strength to try wearing down Mayweather.

Despite the clear advantages numerically, Castillo’s slow start cost him the fight as he only won 1 of the first 6 rounds.

The HBO announce team loudly voiced its disapproval of the verdict, with unofficial scorer Harold Lederman having Castillo winning 115-111.

Mayweather used his quick footwork, combinations and his jab specialty to coast to another unanimous decision victory, this time with all analysts in agreement, including Harold Lederman.

In Castillo's first title defense, he fought former Super Featherweight and future Lightweight champion, Joel Casamayor.

Corrales defeated José Luis Castillo for the WBC lightweight title via TKO in the tenth round.

[3][4][5] Both men stood in front of each other, battering each other with hard combinations and power punches throughout the entire fight.

"[6] Corrales then trapped Castillo against the ropes and landed numerous punches, causing the referee, Tony Weeks, to stop the fight.

"[7] After announcing his retirement in March 2010, Castillo returned to action in a fight against Roberto Valenzuela on June 18, 2010 and won the bout by unanimous decision.