Bottles were thrown at police officers and several people were arrested at the rally, which saw many protesters wearing British flags over their shoulders.
Earlier, Merseyside Police chief Serena Kennedy said her force was “absolutely planning” for further possible disturbances in Southport following the deadly attack targeting children which prompted Tuesday evening’s clashes.
Supporters of the far-right English Defence League (EDL) are suspected of having travelled from outside the area to the seaside town near Liverpool to orchestrate several hours of serious violent disorder.
A 100-strong group attacked police and properties, throwing bricks at a mosque and setting vehicles and other objects on fire.
Police said 53 officers were wounded, at least eight of them seriously, and that they had arrested four suspects.
During a visit there on Wednesday, Kennedy said her officers were “well prepared” and had “sufficient resources”.
But she added: “The people who turned up last night were bolstered very quickly and it very quickly escalated.”
Acknowledging communities in Southport were “really worried” about further disturbances, she added that Merseyside Police would continue to be supported by other regional forces.
That would ensure “that we don’t see a repeat of last night”, she added.
Officers have been granted new temporary powers to disperse any crowds that attempt to gather in the area.
The violence erupted shortly after a vigil was held in the town centre, where hundreds fell silent in tribute to the victims of the stabbing attack that also critically injured five children and two adults.
Police have said they are not treating it as terror-related.
Few details have emerged about the suspected attacker, other than that he is 17 years old and born in the Welsh capital Cardiff. His parents were from Rwanda, according to the BBC.
Police have been granted more time to question him. He cannot be named because of his age.
Hours after the attack, unverified information about the suspect’s background began spreading on social media.
Far-right influencer Andrew Tate had posted a video on social media, viewed by nearly 15 million people, blaming the stabbing on an “illegal migrant”.
The Muslim Council of Britain (MCB) said the Islamophobia backlash started with a false online rumour stoked by misinformation from a Russian news site, wrongfully associating the crime with Muslims.
“At a time of great tragedy, loss, and mourning, we must stand firm against the cynical forces of hatred and division,” MCB secretary general Zara Mohammed said.
Merseyside Police’s assistant chief Alex Goss said there had been “much speculation and hypothesis” about the suspect while “many people who do not live in” the local area had taken part in Tuesday night’s violence.
“What did we do to deserve this? We’ve already lost our children,” 53-year-old Suzanne Jerram, owner of a store that was vandalised, told Agence France-Presse.
“Our community’s grieving, how dare they come here to our town and do this? It’s disgusting, it really is disgusting.”
Shadow interior minister James Cleverly urged the government to respond “hard and fast” to the disturbances and online misinformation.
Meanwhile Deputy Prime Minister Angela Rayner suggested the government may “be looking at” whether to proscribe the EDL under anti-terror laws.
The young victims of Monday’s attack were named the following day.
Nine-year-old Alice Dasilva Aguiar died in hospital early on Tuesday, police said, after Bebe King, six, and Elsie Dot Stancombe, seven, died on Monday.
Reporting by Reuters, Agence France-Presse