River ended a 533-minute goal drought spanning more than five matches as they came from a goal down with two in two minutes to win 2-1 at the Monumental, toppling Godoy Cruz and climbing to 14th.
Independiente, who beat title holders Banfield 3-1, and Estudiantes, 2-1 winners at Tigre, have 30 points from 15 matches, two more than Godoy Cruz and Argentinos Juniors, who visit Arsenal on Monday.
Banfield have 23.
Central defender Leandro Desabato put Estudiantes in front with an early header from a Juan Sebastian Veron corner and forward Jose Sosa added a brilliant solo goal in the 26th minute.
Tigre hit the bar before going two down but reduced the deficit when defender Marcos Rojo headed an own goal trying to clear the ball shortly before half time. Both sides hit the woodwork in the second half.
Independiente, who had lost their previous two games, took the lead midway through the first half when striker Andres Silvera scored his seventh goal of the championship.
Banfield equalised through Ruben Ramirez in the 36th minute but from the re-start midfielder Leandro Gracian hit a shot from the halfway line that dipped under the bar with keeper Cristian Lucchetti stranded to restore the visitors' lead.
Striker Leonel Nunez hit the third in stoppage time.
The atmosphere at River was buzzing as Cappa took his place on the bench for the first time since replacing the sacked Leo Astrada during the week.
Godoy Cruz silenced the home crowd at a packed Monumental when Federico Higuain began and finished off a fine move to put his side in front after half an hour.
Cappa fired River up by sending on midfielder Diego Buonanotte after an hour for his first match since being injured in a December 26 car crash that killed three friends.
Former Argentina forward Ariel Ortega equalised when he tapped in Roberto Pereyra's square ball in the 68th minute and River went ahead within two minutes when Buonanotte broke away and passed to right-back Paulo Ferrari, who ran past the keeper and scored with a left-footed shot past a defender on the line.
