Andy Murray says the build-up to his all-British China Open quarter-final against Kyle Edmund will be "uncomfortable" for him.
The world number two is a Davis Cup team-mate of Edmund, 21, and regularly trains alongside him during off-season.
The Scot, 29, beat Russia's Andrey Kuznetsov in straight sets on Wednesday to go through while Edmund beat Spaniard Roberto Bautista Agut.
Their match is expected on court in Beijing at approximately 08:45 BST.
"It's always a little bit uncomfortable because, normally, when you see your friends and stuff in the locker room you have a chat, joke around," said Murray. "But on match days it always tends to be a little bit more serious."
Edmund, who looks set to move into the top 50 after Wednesday's win, has met Davis Cup team-mate Murray only once before at Tour level, losing in a deciding set on the grass at Queen's Club in June.
The pair are in the same half of the draw as fifth seed David Ferrer of Spain, who beat Italy's Fabio Fognini 6-3 6-4 on Wednesday. World number one Novak Djokovic has won the China Open for four successive years but the Serb withdrew last week.