Five men were dismissed deep into second-half injury time, following an all-in scuffle at the Estadio Julio Humberto Grondona.
The disagreement was down to Arsenal's objection to Gimnasia not handing back possession at the re-start following the match ball needing to be replaced due to a puncture.
Hosts Arsenal saw Damian Perez and Nicolas Aguirre dismissed - the latter for a headbutt - while Gimnasia's Gaston Diaz, Matias Garcia and Franco Mussis were also sent off for their part in the ugliness.
Earlier, Milton Caraglio had put Arsenal ahead, as they looked to capitalise on Newell's Old Boys' slip-up earlier in the matchday.
But Gimnasia's Fernando Pereyra saw the visitors level on 63 minutes to earn them a point on the road - to extend their unbeaten run to four matches.
Arsenal are in second spot, three points behind leaders Newell's - who were also held to a 1-1 draw at home to Godoy Cruz.
Horacio Orzan had the league leaders up on seven minutes, but Godoy equalised on the hour-mark courtesy of Jose Fernandez's strike.
Boca Juniors went level with Arsenal on 24 points, courtesy of their 2-0 success at home to Colon.
Quick-fire goals to Emmanuel Gigliotti - his sixth in five games - and Juan Martinez in the 20th and 21st minutes sent Boca past San Lorenzo, who slipped to fourth after their 3-2 loss away to Lanus.
Lanus led early, then came from behind to beat San Lorenzo, with Jorge Pereyra scoring a brace - netting in the fifth minute to put them ahead, before his 72nd-minute strike gave them the lead for good late on.
Velez Sarsfield made it consecutive victories to climb to ninth in the table, with a 2-0 home result over Argentinos Juniors.
Rosario Central had a slow start to their campaign, losing five of their first seven matches, but are since unbeaten in six - most recently claiming a 1-0 win at Belgrano.
Estudiantes are one point above Rosario in mid-table after a narrow 1-0 triumph at home to Quilmes, while Racing Club finally broke through for their first win of the season with a 1-0 result on the road at Olimpo.
Racing remain in bottom spot with just five points, and have six matches remaining to climb off the foot of the table to ensure they stay in the top flight next season.
All Boys and Tigre played out a 0-0 draw, while Atletico Rafaela's hosting of River Plate also ended scoreless.
