Mauricio Pochettino’s side, who had Sergio Ramos sent off for a second yellow card, have 46 points from 19 games with Nice in second place 13 points behind after a comeback win at home against Lens.
It looked like PSG were destined to lose for just the second time in the league this season before Icardi, who’s become something of the forgotten man in Paris amid the stardom of Lionel Messi, Kylian Mbappe and Neymar, sent his team home with a share of the spoils, heading home an Achraf Hakimi cross.
At Lorient’s Moustoir stadium, PSG were not only without the injured Neymar, but they also had to cope with the suspensions of Mbappe and Marco Verratti and they lacked inspiration.
While Messi had a couple of chances after the break, the visitors had their first shot on target in the 81st minute when the Argentine forward’s strike was parried by Paul Nardi.
Ramos, who had replaced Nuno Mendes at half-time, was then sent off with five minutes left after picking up two yellow cards on a night to forget for the capital side until Icardi headed home.
The result left Lorient second from bottom on 16 points, four ahead of St Etienne who were beaten 1-0 at home by Nantes.