The victim, in her 20s, was left "fighting for her life" after the assault in Victoria Park, Leicester, at about 23:40 BST on Monday.
She was dragged into bushes and found near recycling bins about an hour later, Leicestershire Police said.
The suspect was arrested on Tuesday night and detectives have renewed their appeal for information.
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Police said the woman had been walking alone along a well-lit section of the park before she was attacked about the head and upper body.
Large parts of the public space were cordoned off on Tuesday as forensic officers combed the scene for evidence.
Det Ch Insp Rob Widdowson said: "This was a really brutal attack, the victim has been left with horrendous injuries and is fighting for her life.
"We still need to trace anyone who may have been in the area of Victoria Park [late on Monday night or early on Tuesday morning] and who may have seen something which can help us with our enquiries.
"You may not think what you saw is significant, but we still want to speak to you."
Det Supt Neil Castle added: "Whilst crossing the park she was attacked and subsequently dragged into some bushes, where she was seriously assaulted. She sustained horrific injuries."

Patrick Sookhdeo, 68, of River Street, Pewsey, Wiltshire, is accused of one count of indecent assault on a woman aged 16 or over in Plaistow, east London, in 1977.
The Metropolitan Police said Mr Sookhdeo was arrested following an investigation by Newham detectives.
He was bailed to appear at Thames Magistrates' Court on 4 April.

Some 13,000 people have left the area since Thursday, the UK-based Syrian Observatory for Human Rights says.
The evacuation deal also includes government-held parts of Idlib province besieged by rebels.
The UN envoy for Syria says there are plans for peace talks on 8 February.
Some 7,000 people are still trapped in Aleppo, according to the Syrian Observatory. Conditions there are grim, with no access to food and shelter and minimal medical facilities.
Among those evacuated on Monday were 47 children trapped in an orphanage, children's charity Unicef said in a statement. Some were in a critical condition because of injuries or dehydration, the organisation added.
The evacuees also included seven-year-old Bana Alabed, whose home in eastern Aleppo was bombed and whose appeals for peace on Twitter were heard worldwide.
In a video she expressed relief at escaping the "endless bombardment in Aleppo".
After leaving Aleppo city, the evacuees will be moved to parts of Aleppo and Idlib provinces.
The operation restarted late on Sunday. It had stalled after armed men set fire to buses that were about to transport the sick and injured from the mainly Shia, government-held villages of Foah and Kefraya in Idlib province.
The Syrian Observatory said that 500 of the 4,000 villagers left the areas on Monday.
A rebel representative said hundreds of people would also be evacuated from Zabadani and Madaya, two army-besieged rebel towns near the border with Lebanon, as part of the deal.
At the UN Security Council, the 15 members managed to overcome disagreements between Western nations and Russia and unanimously approved the resolution.
It requested the "UN and other relevant institutions to carry out adequate, neutral monitoring" of the mass evacuations from Aleppo.
Syria's envoy Bashar Jaafari spoke out against council members who he said had hidden agendas and intended "to legitimise foreign interference, the changing of legitimate governments by force, or even using military force".
For monitors to be deployed in Aleppo, they need permission from the Syrian government.
Meanwhile, a gunman killed the Russian ambassador to Turkey in Ankara. The attacker, identified as a police officer, shouted "Don't forget Aleppo".
Leaders of both countries, who brokered the deal for the evacuations, said the attack was a "provocation" aimed at hurting bilateral ties, and vowed to investigate the killing. It was not clear if the gunman acted alone or had links to any group.
A 17-year-old boy has been arrested on suspicion of attempted murder over a "horrific" attack on a woman in a park.
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A man has been charged with carrying out a sexual assault on a woman almost 40 years ago.
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The UN Security Council has adopted a resolution calling for UN officials and others to monitor the mass evacuations from rebel-held east Aleppo and the safety of civilians still there.