Great Britain and world champions Spain will clash on Tuesday following opening day EuroBasket Group C setbacks in Warsaw.

Britain battled, coming back from a 14-point deficit to lead in the second quarter against Slovenia but ultimately saw their hopes of an upset disappear in the final period when Jure Zdovc's team rode the back of big man Erazem Lorbek to a 72-59 victory.

Meanwhile, Spain dug themselves a 19-point hole against Serbia that they weren't able to climb out of and crashed to a surprising 66-57 defeat.

"I have full trust in this team and I know the players will believe in themselves in the coming games," said Sergio Scariolo, Spain's third coach in as many summers.

Spain were unrecognizable from the side that has been among the best in the world in recent years.

Pau Gasol had a nightmare night, which included a woeful one-of-eight effort at the free-throw line, and finished with nine points.

He missed all of Spain's friendly games before the EuroBasket after having a finger operation.

"Pau has been a long time without playing and you could see that," Scariolo said.

Spain were also without Rudy Fernandez, who is out of action with a quadriceps injury.

"I don't know if Rudy will be able to play or not," Scariolo said.

"I will ask my players to increase their level of competitiveness and that we really play as we know we can.

"Against Serbia, we were awful in shooting and we allowed too many easy shots."

Gasol, the most valuable player of the 2006 FIBA World Championship, says Spain can use the setback against Serbia to get stronger.

"We have to learn from this defeat," he said.

"We have a bad game and we didn't start as we would have wanted, but against Great Britain we have to win at all costs.

"We have to play hard and try to grow throughout the tournament."

He warned Tuesday's opponents: "The game against Britain will be a different game altogether."

Britain coach Chris Finch is fully aware that his players could face a backlash against Spain.

"It doesn't get any easier," he said, "but we knew the schedule way back when.

"That's not changed. What's important is that we stay committed to what we want to do.

"We did that for about 35 minutes (against Slovenia). Tonight we're going to have to do it for 40 to have a chance to win."

Last Time Out: Spain beat Great Britain 84-63 in a pre-EuroBasket friendly in August.

Key Match-Up: Spain backcourt v Britain backcourt. A perceived weakness before the EuroBasket, Britain's guards Nate Reinking, Flinder Boyd, Mike Lenzly and Jarrett Hart held their own against Slovenia while Spain's Ricky Rubio, Juan Carlos Navarro, Raul Lopez and Carlos Cabezas were out-played by their Serbian counterparts.

X-Factor: Boyd. On a team lacking outside shooting, Boyd hit some big shots and delivered some fine passes to help Britain stay close to Slovenia.

Key Stat: 12 steals. That's how many Serbia had against Spain, who were bothered all night by the Blues' pressure.

Sounding Off: "That's why you play basketball. You want to play against the best. We're disappointed with the loss (against Slovenia), but it's going to be easy to get up in the morning" - Britain's Nate Reinking, when asked about the hard game coming up against world champions Spain