* Promoted All Boys upset Estudiantes 2-1
* Banfield crush ailing Independiente 4-0
* Palermo hat-trick gives Boca 3-1 victory (adds later results)
Promoted All Boys, back in the Argentine first division for the first time in 30 years, upset title favourites Estudiantes 2-1 on Sunday to leave San Lorenzo as sole leaders.
Independiente coach Daniel Garnero's future looked bleak after his side's 4-0 trouncing by Banfield left them bottom of the standings, still without a win after seven rounds of the Apertura championship.
Boca Juniors, whose poor start to the season included a 2-0 defeat by All Boys, beat Colon 3-1 at home with a hat-trick by veteran striker Martin Palermo, taking his tally to five in three matches and a record 227 for the club.
San Lorenzo beat another promoted side, Olimpo, 3-1 at home on Saturday to lead the standings with 15 points. They are one point ahead of Velez Sarsfield and two in front of Estudiantes, Arsenal, Banfield and River Plate, who lost 1-0 away to Newell's Old Boys in Rosario.
Independiente, one of Argentina's so-called 'big five' clubs, crowned South American champions a record seven times and only pipped to the post in the 2009/10 Clausura championship in May, have struggled badly since letting coach America Gallego go.
The decision was part of cost cutting as they prioritise completion of their remodeled Libertadores de America stadium but they are paying a high price in poor performances which could cost the relatively inexperienced Garnero his job.
Boca, who fell behind early on, are mid-table on 10 points after Palermo netted three fine goals and missed a penalty. His equaliser was the best when he took a square pass from defender Matias Caruzzo and chipped goalkeeper Diego Pozo.
All Boys, also with 10 points, went ahead at their small Malvinas Argentinas ground when central defender Eduardo Dominguez tapped in from close range after a poor Estudiantes clearance at a corner.
Rodrigo Brana equalised on the stroke of halftime, ghosting through the middle unmarked to head home a cross from the right but midfielder Sebastian Grazzini chipped a brilliant 50th-minute winner for All Boys.
Racing Club, another of the big five clubs which also include River, Boca and San Lorenzo, ended a run of four defeats with a 4-0 win on Friday over nine-man Lanus, who had two players sent off between the 45th and 65th minutes.