Black Stars striker Jordan Ayew provided an assist for Crystal Palace in their 2-1 defeat to Chelsea on match week eight of the English Premier League.
Ayew put up an impressive display but it was not enough as the Eagles lost at Selhurst Park.
Substitute Gallagher, who impressed on loan at Palace last season, curled home a superb right-footed effort to snatch victory for Chelsea with his first goal for the club.
Pierre-Emerick Aubameyang also scored his first Chelsea goal on his Premier League return after Odsonne Edouard had poked Palace into an early lead.
However, there was controversy surrounding Aubameyang’s goal as it was set up by Thiago Silva, who Palace felt should have been sent off for a deliberate handball which denied Jordan Ayew a possible goalscoring opportunity.
Ayew has made seven league appearances for Crystal Palace this season and provided two assists in the process.