Frustrated by their inability to put the ball in the net in a Champions League defeat to Real Madrid in midweek, PSG saw Angel Di Maria open the scoring on their return to domestic duty before Ibrahimovic got a double either side of a Lucas Moura goal. Ezequiel Lavezzi completed the rout.
The win saw the reigning French champions continue their unbeaten start to the domestic season as they made it seven league victories in a row.
The Parisians may be forgiven if they lose no sleep over high-flying Caen, in second place, who closed the gap to 11 points with a tight 2-1 win at home over Guingamp in one of Saturday’s late games.
The campaign is only 13 games old but PSG are already 13 points ahead of Lyon and Saint-Etienne – who meet on Sunday evening – as well as Angers, who were beaten 2-0 at home by Rennes on Friday.
“We are not yet champions but if we continue like this we can win it soon,” Lucas told Canal Plus.
“We can go down in history. To not lose a match is our objective.”
Laurent Blanc’s charges let themselves down with poor finishing as they succumbed to a 1-0 defeat at Real Madrid in midweek, but their poise was better on Saturday and it was a day to forget for struggling Toulouse.
The visitors started the day in the relegation zone and had not won in 11 league games since the opening weekend of the season, so an away win would have been an enormous upset.
Paris just six minutes to open the scoring thanks to Di Maria, whose dead-ball delivery from 40 yards was not intended as a shot, but evaded everyone on its way into the net.
The hosts continued to create openings but their second goal in the 18th minute was something of a gift from the Toulouse defence as on-loan Monaco man Marcel Tisserand inexplicably headed the ball back across his own six-yard box to leave Ibrahimovic a simple finish.
The Swede and Di Maria both had chances to increase the advantage prior to the interval while Edinson Cavani was denied by a good Ali Ahamada save at the start of the second half before Toulouse created their first opportunity of note from a Jean-Daniel Akpa-Akpro ball across the box that passed just beyond the reach of Martin Braithwaite.
Blanc freshened up his attack with the introduction of Lucas and Lavezzi in place of Cavani and Di Maria, and it was the Brazilian who made it 3-0 on 66 minutes, starting the move and then continuing his run to the back post where he headed home Gregory van der Wiel’s cross.
Lucas played his part in the fourth goal which arrived with a quarter of an hour remaining, as his shot was beaten away by Ahamada and Ibrahimovic arrived to convert the follow-up.
Lavezzi put the seal on an utterly comprehensive win with just his second of the season on 78 minutes as PSG extended their unbeaten run in Ligue 1 to 22 matches since March.
In other late games, tiny Gazalec-Ajaccio got a crucial three points at Reims with a 2-1 win that lifted them to third from bottom.
Level with them on 12 points are Montpellier, who clinched a last gasp 2-1 win at home to Nantes.
Lille climbed to 16th with a late goal giving them a 1-1 draw with Bastia while rock bottom Troyes, the only team in Ligue 1 still without a win, were beaten 4-1 at Lorient.
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