The Liberals have claimed victory in a Victorian byelection that was essentially a dress rehearsal for the state's November poll - though the performance got mixed reviews from critics.

With about 80% of the vote counted in the Mornington Peninsula seat of Nepean, Liberal candidate Anthony Marsh bagged 38.5% of the primary vote and a commanding 63.4% on a two-candidate basis. However, the Victorian Electoral Commission initially treated the two-candidate race as a contest between Marsh and independent Tracee Hutchison - until One Nation’s Darren Hercus muscled into second place with 24.7% of the primary vote to Hutchison’s 21.3%.

Marsh, who graciously accepted the honour of representing people he technically can't vote for himself (he admitted he doesn't live in the electorate), declared: “I’m so glad I could bring it home for you tonight.” He vowed to fight for Nepean daily ahead of “one of the most important state elections that we’ve seen.”

Opposition leader Jess Wilson welcomed the result but conceded the party still had some homework to do before November. Labor, in a move that could be interpreted as either strategic brilliance or tactical surrender, opted not to field a candidate. Despite retaining the seat, the Liberals suffered a nearly 10% swing against them on the primary vote.

The byelection was triggered by the sudden resignation of former Victorian Liberal deputy leader Sam Groth, whose party has held the seat since its inception except for a four-year Labor interlude.

One Nation’s Hercus, who spent election day without the physical presence of leader Pauline Hanson (she campaigned with him earlier but was absent on polling day), reported mixed feedback from voters “fed up with empty promises.” He noted some Liberal voters had defected out of frustration with their own party.

Independent Hutchison, who campaigned on being “of this place,” lamented that the area had been “overlooked and let down by the major parties for decades.” The electorate includes wealthy postcodes like Sorrento, Portsea, and Flinders, alongside lower socioeconomic areas such as Capel Sound, and suffers from a notable lack of public transport and a promised revamp of Rosebud hospital.

Monash University senior politics lecturer Benjamin Moffitt warned that One Nation’s strong showing - consistent with national polling and the South Australian election result - could spell trouble for the Liberals in November. “If they even do somewhat well in Nepean, that’s a real problem for the Liberal party,” he said.

So the Liberals won a seat they already held, with a candidate who can't vote for himself, against a field that included a no-show Labor party, a surging One Nation, and an independent who thinks the major parties have let everyone down. Dress rehearsal? More like a warm-up act for a very long November.