After the man left, Mr Patel said two others came into the store, which he had owned for five years without incident.
They were wearing black hoodies, and demanded he give them the till drawer.
"I was behind the counter. They grabbed my shoulder and shouted, 'Give me your money.' They had a knife. One took the till and ran outside, and the other stayed and asked me to open the cigarette cabinet."
It held only a couple of packs, which the robber took, then fled.
"My wife was next door. She saw what was happening on CCTV and called the police, then came in with a hockey stick. I took it and ran out to their getaway car and smashed the front passenger window with it."
The men then ran up Oranga Ave, leaving the stolen goods in the car.
Mr Patel pulled from the car the till and his iPhone - which was stuck to the drawer with a magnet.
The robbery is one of a string of incidents where violent, often young offenders have demanded cash and cigarettes.
In one such attack, in March, about 10 teens robbed Redhill Superette in Papakura, taking cigarettes and an iPhone 6. Staff defended themselves with a cricket bat and a hockey stick.
After it, police said they were running workshops for dairy and liquor store owners in South Auckland to advise them on what to do in such situations.
That same month, six teenage girls brutally attacked a young Papatoetoe shop worker before making off with cash and cigarettes. Last week, two girls, aged 14 and 16, were charged with aggravated robbery.
At the time, Retail New Zealand spokesman Greg Harford said his organisation was receiving increased reports that thieves were targeting alcohol and tobacco, which could be sold on the black market.
Earlier this year, Counties Manukau police set up a special investigations unit to solve 10 aggravated robberies at local service stations where cigarettes had been targeted.
In a second liquor store burglary and police chase this week, a gaggle of teenagers in a stolen car and throwing bottles out its windows led police on a chase around South Auckland early this morning.
After being chased along the motorways around the southern suburbs, the fleeing car was blocked at Te Irirangi Drive where police arrested the teens, aged 15 to 17.
Property was found in the car linking the teens to a liquor store burglary at the Greenhithe Liquor Centre, in Greenhithe Rd, just after midnight.
On Wednesday morning police failed to catch another group of burglars who had robbed the Oteha Valley Liquor Centre.
Two cars were spotted shortly after the burglary, police managed to chase one but gave up chase after it entered the Southwestern Motorway the wrong way at the Cavendish Rd on-ramp.
University of Canterbury criminologist Professor Greg Newbold said the robbers were generally "desperate young losers who haven't thought about the consequences of what they're doing, which are horrific compared to the benefits of taking home some cash and a few packs of cigarettes".
On Wednesday, police confirmed they had caught one of the alleged robbers of Mr Patel's Penrose liquor store and a dog unit was tracking the second.
Yesterday, Mr Patel said he believed police had arrested the second suspect. Despite this, he still felt nervous in the shop.
"I didn't sleep last night, but I will just keep working here because there's not anything else to do."
Mr Patel has not told his children, aged 4 and 12, what happened, because they enjoy playing in the shop and sometimes sitting on the counter while he works, and he doesn't want them to be afraid.
He said he didn't believe the attackers were from the Penrose/Oranga area. "The local people are good people here."
