Pakatan Harapan chairperson Dr Mahathir Mohamad has conceded that he had expected his coalition to lose the Tanjung Piai by-election.

However, he did not expect to be trounced.

"I accept the decision made by the people of Tanjung Piai, although (I had) expected our opponents to have the majority.

"I had predicted that (our opponent's) majority would not exceed 2,000 votes.

"However, the official results showed that the gap was 15,086 votes," Mahathir said today in a statement, which he signed off as the Harapan chairperson.

He promised that all coalition parties will conduct a "detailed, serious and honest" assessment of what went wrong.

He also thanked all the party activists for their work during the campaign.

On Saturday, Tanjung Piai voters delivered the worst parliamentary by-election result ever for an incumbent federal government.

Harapan secured only 26.4 percent of the votes. In contrast, BN secured 65.6 percent of the votes, up 19.5 percent from the general election last year.

According to Malaysiakini's analysis, there was a huge swing in Chinese votes and a marginal swing in Malay votes, away from Harapan.