Steven McMyler, 34, was targeted as he sat on a bench within the grounds of Wigan parish church in the early evening of August 6 last year.
Shortly before, the joiner had been drinking in a nearby town centre pub with another man, Lewis Peake, 29, who decided to rob the expensive 18-carat Submariner watch he was wearing, it is alleged.
Peake first tried to persuade two youths outside The Raven pub to help him rob Mr McMyler, and was said to have promised £100 to assault him, Manchester Crown Court heard.
The offer was rejected, said prosecutor Mark Ford QC, but Peake was “not so easily deterred in the execution of his plan” as he and Mr McMyler walked to the church gardens.
Four males from Merseyside – Jordan Short, 20, Michael Wilson, 20 and two youths aged 14 and 17, arrived at Wigan Wallgate train station at 7.12pm and seven minutes later walked up to the entrance of the church garden.
Mr Ford said: “Purely by chance they were seen to encounter the other defendant, Peake, and the death of Mr McMyler would follow shortly.
“There is no suggestion that Peake was acquainted with these four people, who had travelled from Liverpool.”
A short discussion between them took place, and grainy CCTV footage captured the attack on Mr McMyler as he was surrounded by the group, the court heard.
Mr Ford continued: “Despite the poor quality of the footage, we say it is apparent that the defendants engaged in a joint enterprise to rob Mr McMyler.
“To put it in simple terms, we say they were all in it together.
“During the course of that incident Mr McMyler was kicked forcefully to the head. The Crown say that kick was delivered by Jordan Short.
“It is not thought that Mr McMyler ever regained consciousness after that kick.
“In the course of a violent robbery carried out, we say, by these five men, that watch was taken and the assault he suffered at their hands cost Steven McMyler his life.”
The prosecutor said matters took a “rather unpredictable turn” as Mr McMyler lay dying when the Liverpool group turned on Peake.
One of them, believed to be the youngest defendant – aged 13 at the time – struck him over the head with a bottle as they demanded cash.
After a bleeding Peake ran away they too dashed from the church, and were said to be “laughing or grinning” as they took a taxi back to Merseyside, said Mr Ford.
Jurors were told that Short was unwell and not able to participate in the trial.
The period before his death appeared to be “rather troubled” for Mr McMyler, said Mr Ford, as his relationship broke down with his partner, and his parents, James and Carole, were worried he was drinking too much and on occasion using drugs.
Mr McMyler had recently opted for a “clean break” by travelling to Thailand, but decided against it when he realised he needed to self-isolate for a fortnight because of the Covid-19 pandemic.
He returned from London to his home on the afternoon of August 6 and still had his suitcase with him.
The court heard Peake later returned to the attack scene as Mr McMyler lay unconscious “with his face purple”, and did not check on him as he made off with his phone and suitcase.
When arrested, Peake denied he was involved with the watch robbery, and claimed he was a victim after the Liverpool group took £200 from him.
He said one of them had “volleyed” Mr McMyler to the head.
The watch has never been recovered.
Peake, of James Street, Little Lever, Bolton; Wilson, of Northfield Close, Kirkby, and the two youths, who cannot be identified for legal reasons, all deny murder, an alternative count of manslaughter and conspiracy to rob.