Police were called to Vanbrugh Road at around 9:30pm after reports of a shooting.
The victim, a 30 year old man, was found inside the property with injuries “consistent with shot gun discharge“. He was given first aid by paramedics on the scene.
His condition is serious but stable and not life-threatening.
Detectives suspect that the shooter knocked on the door, where another person answered but ran away.
Chief Inspector Dawn McNally, from Merseyside Police, said: “This was a brazen and targeted attack and we are determined to bring the person responsible to justice.
“The victim was in his house at the time but fortunately has not suffered life-threatening injuries.
“We will not tolerate the use of guns on the streets of Merseyside and we will do all we can to protect communities from the criminals who use them.”
House-to-house enquiries are being carried out and a portion of Vanbrugh Road remains cordoned off this morning. The incident is being treated as a targeted attack.
Anyone with information on the attack is urged to call Crimestoppers anonymously on 0800 555 111 or the gun crime hotline on 0800 230 0600.