MONTREAL -- The Opposition Parti Quebecois retained two ridings in byelections Monday in what was widely viewed as Jean-Francois Lisee's first major test since he became leader of the sovereigntist party.

The governing Liberals won their Montreal stronghold of Verdun but saw their share of the popular vote drop in all four byelections when compared with their performances in 2014.

One of the PQ victories came in Saint-Jerome, which had been vacant since former leader Pierre Karl Peladeau's resignation from politics last May.

Marc Bourcier had more than 45 per cent of the vote for the PQ, with more than 80 per cent of polls reporting. That compares with the 36.8 per cent garnered by Peladeau in the 2014 election.

The PQ also kept its stronghold of Marie-Victorin, a Montreal-area riding last represented by the party's ex-house leader, Bernard Drainville. Catherine Fournier had more than 50 per cent of the vote, outdistancing Drainville's 38.2 per cent from two years ago.

"What a beautiful evening," Lisee said, pointing out Fournier, at 24, will become the youngest woman ever elected to the national assembly.

In other byelections Monday, Isabelle Melancon won Verdun for the Liberals, while the Coalition for Quebec's Future's Eric Lefebvre easily won Arthabaska, which had been vacant since Sylvie Roy's death earlier this year.

Roy won the riding for the Coalition with a hefty majority in 2014 before she became an Independent a year later.

The results will have little impact on the standings in the 125-member legislature. The Liberals have 70 seats, the PQ 30 and the Coalition 21. There also three Quebec solidaire members and one Independent.