Copa Libertadores semifinals filled with mix of old and new faces

Time to change the chip and flip the switch. Quality international football soon returns to South America; the most competitive World Cup qualifying campaign on the planet gets underway in October. But with the 2015 Copa America now part of history, the time has come to refocus on the club game and the semifinals of the Copa Libertadores, which start Tuesday.

Action shut down after the quarterfinal stage at the end of May. This year's fairy-tale club might regret that seven-week pause.

Guarani of Paraguay were in a fine groove back in April and May. They knocked out giant after giant without conceding a goal. From the moment early in the competition when Spanish coach Fernando Jubero opted to play with a back three, Guarani have been punching well above their weight. They've been boosted by the fact that veteran Julio Cesar Caceres has been in magnificent form in the middle of the defensive line, reading the danger to his goal and snuffing it out with quiet efficiency.

Corinthians of Brazil and Racing of Argentina were eliminated without Guarani's defence being breached. Now, after the long break, they aim to do the same to River Plate, starting Tuesday in Buenos Aires.

But it will be a slightly different River from the one that stuttered through much of the competition before catching form and sealing a semifinal place with a memorable 3-0 win at Cruzeiro of Brazil. That night's hero, Colombian striker Teo Gutierrez, is on his way out, seemingly to Sporting Lisbon of Portugal.

Older heroes have returned, though. Striker Javier Saviola and midfielder Lucho Gonzalez have come back to the club after years in Europe. In 2001, when these two clubs met in the group stage of the Libertadores, River won 4-0 in front of their own fans, with Saviola scoring twice and Fernando Cavenaghi -- another who has left and returned -- adding another.

Can River turn back the clock 14 years? Guarani would be happy to go back seven weeks, though the Paraguayans looked unfazed at the weekend and won 5-0 at General Diaz in the second round of the domestic championship.

Wednesday's semifinal is in Porto Alegre in the south of Brazil, where Internacional host a team who have traveled from the north of Mexico. There is another difference, apart from the geographic distance between Inter and Tigres of Nuevo Leon. The Brazilians have been in constant action; their domestic championship did not shut down during the Copa America. Inter would seem to have all their sights trained on the Libertadores because they languish 12th in the table.

Tigres, meanwhile, have not been in competitive action. Their players went on holiday before meeting up for preseason work on the Caribbean coast. If this makes their form something of an unknown, this is enhanced further by the fact that the club has its check book out. They have brought in highly rated, young, Mexican midfielder Jurgen Damm, as well as two intriguing foreign signings: centre-forward Andre-Pierre Gignac from Marseilles and Nigerian striker Ikechukwu Uche from Villareal.

This could backfire. Tigres have the best attacking record in the Libertadores, and the blend up front of the skill of Brazilian Rafael Sobis -- a one-time Internacional idol -- and the pace of Ecuadorian Joffre Guerron have been among the standouts of the team. Brazilian coach Ricardo Ferretti will hope to find a way to incorporate his new talents in a way that benefits the team. But with no competitive matches behind him, we will have to wait for the evidence of Wednesday's intriguing first leg of the semifinal.