Complex sentence: Under manager Julio César Falcioni, they won the 2009-10 Apertura tournament, their first Argentine Primera División championship, with a record of 12 wins, 5 draws and 2 losses.
Split into simpler sentences: Under manager Julio César Falcioni, they won the 2009-10 Apertura tournament. This was their first Argentine Primera División championship, with a record of 12 wins, 5 draws and 2 losses.