BUENOS AIRES, June 12 - Playmaker Juan Roman Riquelme will hold the key as Boca Juniors attempt to unlock Gremio's defence in the first leg of the Libertadores Cup final at the Bombonera on Wednesday.

Last year Riquelme played a major role in leading unfashionable Spanish club Villarreal to the Champions League semi-finals, where they lost to Arsenal.

After falling out with Villarreal coach Manuel Pellegrini, Riquelme has returned to Boca on loan and again been the main figure in taking them to the final of the Champions League's South American equivalent.

Riquelme produced a brilliant display as Boca won 2-0 away to Paraguayan champions Libertad in the second leg of their quarter-final, having been held 1-1 at home.

He also scored the first goal as they beat Colombian surprise package Cucuta 3-0 in their semi-final second leg last week, overturning a 3-1 deficit from the first game.

Boca, beaten by Colombian provincial side Once Caldas in their last appearance in the final three years ago, have won five Libertadores Cup titles and another would put them one behind record-holders Independiente.

Gremio, twice former winners, have reached the final only 18 months after hauling themselves out of the Brazilian second division.

Under coach Mano Menezes, they are hoping to upstage their bitter Porto Alegre rivals Internacional, who won the competition last year.

Midfielder Tcheco promised that his side would not be intimidated by the atmosphere at the notorious Bombonera stadium.

"Players have to get used to this sort of pressure," he said, adding that the days of dirty tricks for which the Libertadores was once famous were in the past. "Nowadays, this is just mystique."

Gremio's preparations for the match were hit by logistical problems as they were prevented from travelling to Buenos Aires on Monday because of dense fog in the Argentine capital.

Teams:

Boca Juniors - Mauricio Caranta; Hugo Ibarra, Daniel Diaz, Claudio Morel Rodriguez, Clemente Rodriguez; Pablo Ledesma, Ever Banega, Neri Cardozo; Juan Roman Riquelme; Rodrigo Palacio, Martin Palermo

Gremio (possible) - Sebastian Saja; Patricio, William, Teco, Lucio; Sandro Goiano, Diego Gavilan, Lucas, Tcheco; Carlos Eduardo, Diego Souza

Referee: Jorge Larrionda (Uruguay)