Marseille, who host St Etienne on Sunday, are top of the Ligue 1 table with 68 points from 33 matches, five points ahead of second-placed AJ Auxerre. The Burgundy side travel to Toulouse for their next game.
Marseille have won their last six league matches but Lucho, who joined the club during the close season from Porto, warned against complacency.
"There are still five matches left and we have to take them one by one," he told Marseille's website. "We must not think we're there yet."
Lucho, who has earned the nickname 'El Comandante' for his on-field leadership skills, is keen to earn a place in Argentina's squad but knows the competition is fierce.
The South Americans have Fernando Gago, Maxi Rodriguez, Javier Mascherano, Esteban Cambiasso and Juan Sebastian Veron vying for midfield places.
However, Argentina coach Diego Maradona stopped by Marseille's training ground a few weeks ago, suggesting Lucho could make the trip to South Africa.
"Diego Maradona did not tell me anything good or bad," said Lucho, who made three appearances for Argentina in the 2006 World Cup finals.
"Argentine has a lot of great players and I will have to be good with my club to be picked. I will hope until the end."
Third-placed Olympique Lyon will host Monaco on May 12 after the French League postponed the fixture to allow the seven-times champions to prepare for their Champions League return leg against Bayern Munich next Tuesday.
Defending champions Girondins Bordeaux, in sixth place with 57 points but with a game in hand, travel to Lorient on Saturday.
Montpellier, who have not won in their last four games, will be at Nancy, also on Saturday.
‘After Manchester City’s recent form, maybe they’re the underdogs against Manchester United!’ Former Red Devils defender on this weekend’s derby
‘Arteta, Alonso, Emery, me… none of us were physical players – we needed the understanding of the game. That probably helped us move into management’: Premier League boss reveals reasons for natural career progression
