San Lorenzo in make-or-break match with San Luis

MONTERREY, Mexico (AP) -San Lorenzo coach Miguel Angel Russo wants his Argentine club to take a win-at- all-costs approach to the Copa Libertadores clash with Mexico's San Luis when the group stage gets back into full swing this week.

After more than six weeks of competition, only Paraguayan club Libertad is guaranteed a berth in the last 16. Several high profile clubs are struggling to qualify for the 16-team knockout round.

Searching for a first Copa Libertadores title, San Lorenzo has stalled in third place in Group 8 with three points from four matches.

San Luis, which finished atop the Mexican Apertura championship last season, has fared even worse in the regional competition, languishing bottom of the group with just two points. But a win for either club would revive qualification hopes.

"It will be a life or death match,'' Russo told reporters after a domestic league match against Arsenal de Sarandi. "The only thing I know is we are not dead and we are going to give everything. The (Libertadores) Cup has a thousand stories; it's about suffering.''

Both San Lorenzo and San Luis will hope runaway group leader Libertad records a fifth straight win against Universitario of Peru, second on five points, on Tuesday. Victory for the Paraguayans would intensify the three-way scrap for the second qualification spot.

Another major Argentine club to be struggling in the group stage is River Plate. A 3-0 away loss to Uruguayan group leader Nacional has dropped the Buenos Aires club to third place in Group 3 with one win from three matches.

Coach Nestor Gorosito said new tactics and new personnel was needed to get the team back on track.

"Once the home and away stage of the cup starts, we are going to change the way we play,'' he told the Cronica newspaper. "First, we have to qualify.''

River face the return match with Nacional in the Monumental stadium on Tuesday, when second-place Universidad San Martin of Peru travels to bottom club Nacional of Paraguay.

Defending champion Liga de Quito also needs a win in the return match against Chile's Colo Colo in Group 1 on Thursday.

Liga lost to Colo Colo away at Santiago last time and sits perilously in third place, three points behind the Chileans and Brazilian cup winner Sport Recife. Sport hosts fellow Brazilian club Palmeiras, bottom with zero points from two games, on Wednesday.

By contrast, Boca Juniors have had fewer problems navigating the group stage. Coach Carlos Ischia said the Copa Libertadores was "No. 1 priority'' for the pre-tournament favorites - particularly when fixture congestion puts strain on his squad.

"We have possibilities in lots of places. Sometimes it's difficult to decide. You have to cope with the circumstances,'' Ischia told a press conference.

The Argentine club's domestic form is patchy and performances in the Libertadores have also failed to convince, despite leading Group 2 with three wins from three.

Nonetheless, a win at home against bottom club Guarani of Paraguay on Thursday would seal Boca's progression to the last 16.

Another leading title contender, Brazil's Sao Paulo, is aiming to extend its lead in Group 4 with a home win over third-place Defensor Sporting of Uruguay on Thursday. Sporting is tied on four points with Colombia's Independiente Medellin, with fellow Colombian side America de Cali bottom with two.

The week's other matches include two Group 7 clashes, with Brazilian group leader Gremio hosting Aurora on Tuesday, while Boyaca Chico of Colombia travels to Universidad de Chile on Wednesday.

Second-place Estudiantes of Argentina host leader Cruzeiro of Brazil in Group 5 on Wednesday.