El Segundo, Calif. ? Kobe Bryant loves a challenge — always has, always will.

Bryant, Shaquille O’Neal and the rest of the Los Angeles Lakers have overcome every obstacle in their way since Phil Jackson was hired to coach them in 1999.

The three-time defending NBA champions never have had a challenge like this.

Not only do they trail the San Antonio Spurs 2-0 in their second-round playoff series, the Lakers are missing two key players — forwards Rick Fox and Devean George.

“It makes it pretty tough,” Bryant acknowledged with a thin smile Thursday.

Their absence was glaring in every way in San Antonio’s 114-95 victory in Game 2 Wednesday.

And it has decimated a bench that was already thin.

Fox tore a tendon in his left foot in the Lakers’ first-round series against Minnesota and will undergo surgery next week.

That made a starter out of George, but he sprained his left ankle in San Antonio’s series-opening 87-82 victory Monday night.

An MRI Thursday confirmed George had what team spokesman John Black called a severe sprain and nothing more. Jackson said it was a virtual certainty George wouldn’t play tonight in Game 3 at Staples Center.

The Spurs won 18 of their last 20 road games in the regular season to finish 27-14.

Seven NBA teams have rallied from a 2-0 deficit to win a best-of-seven series, with the Houston Rockets being the most recent to accomplish the feat, doing so in the 1995 Western Conference finals against Phoenix.

Boston also faces deficit

Boston — The Boston Celtics need another Game 3 playoff comeback against the New Jersey Nets.

Last year, the Celtics overcame a 21-point deficit in the fourth quarter in the third game of the Eastern Conference finals and beat the Nets as Boston fans taunted Jason Kidd.

Tonight, the Celtics play at home after dropping the first two games of the best-of-seven conference semifinals in New Jersey. And the critics in the stands should be back to berate the Nets’ playmaker.

The fans may be as sharp-tongued as a year ago, but a win would still leave Boston behind 2-1. Last year, it went up 2-1 after the biggest fourth-quarter comeback in NBA playoff history.

After that loss, the Nets won the next three playoff games and are 8-1 against the Celtics since, including 3-1 this season.