For the Trojans, the week leading up to the Big Dance is defined by one particular emotion: uncertainty.

Heading into today’s quarterfinal contest at noon against the California Golden Bears, the Trojans’ future is unquestionably hazy. A season full of impressive wins (Tennessee, Texas, Arizona, UCLA, Washington) and head-scratching losses (Bradley, Ryder, TCU, Oregon) leaves USC (18-13- 10-8) with work still to be done before the NCAA’s Selection Committee determines whether USC will be included in the field of 68.

USC coach Kevin O’Neill believes in his team, although he told the team this week that to play postseason basketball, simplifying the challenges ahead will be key.

“If we are good enough to be in the field of 68, we will be there,“ O’Neill said. “We need to take one game at a time, try and win the tournament and leave the rest up to the committee who does this job year round.”

Heading into today’s matchup with Cal (17-13, 10-8), USC leads the Pac-10 in scoring defense, allowing teams to score just under 63 points per game.

Although the team is led by senior guard Marcus Simmons, who was named the Pac-10 Defensive Player of the Year this week, in two regular season games against the Bears, the Trojans have struggled at the defensive end. California is the only team in the conference to score more than 65 points twice against USC all year — a trend O’Neill admits must end today if the Trojans want to fulfill bigger aspirations.

“[California] is really explosive offensively,” O’Neill said. “Their big guys give our big guys trouble because they are a little bit quicker and as a team they score from every spot.”

The two teams have split the season series, with both teams winning on the others’ home court. USC won most recently 78-75 on Feb. 17 at Haas Pavilion, in a game in which freshman guard Maurice Jones scored 22 second-half points off the bench.

California drew first blood Jan. 22 at the Galen Center, as junior forward Harper Kamp’s 18 points and stingy defense on USC’s junior forward Nikola Vucevic (a season-low six points) gave the Bears a 68-66 victory.

Several players recognize the team has a lot to prove today and into the rest of the weekend.

“I don’t know if we really have done enough yet, so it’s important we just got out there and try to win every game,” Simmons said. “If we lose this game, we probably won’t be in anything, not even the NIT. So we want to go out there and play strong and hopefully get to the NCAAs”

Despite being named as one of ESPN Bracketologist Joe Lounardi’s “Last Four Teams Out,” recent conference tournament history might be on the side of the No. 4 seeded Trojans.

In 2009, the last time USC was eligible to compete in the Pac-10 tournament, the No. 6 seeded Trojans won the conference postseason championship with wins over three of the top four seeds.

Most of this year’s leading contributors, including Vucevic (17.7 points and 10.3 rebounds per game) and senior forward Alex Stephenson (9.9 points and 9 rebounds per game) were not key players for the 2009 team.

USC, however, is the only team in the conference this year to beat each of the tournament’s top three seeds: Arizona, UCLA and Washington.

If the Trojans advance to the semifinals with a win over California, they will play the winner of Arizona/(Stanford or Oregon State) on Friday night at 6 p.m.