Mari made his first appearance for the Gunners since arriving from Flamengo on loan last month, while Holding is returning from injury.
Speaking after the game, Bould said: "It's fabulous for the young players to play alongside them. It's a learning programme and we don't very often get older boys and men playing with us, and that's how I learned my game when I was a kid so it's something we miss out on lots of times. It was actually a very good game for them to come in to.
"I think Chelsea's striker is a good player and they have good players all over the park so it was a good test for them and a good 45 minutes. I'm sure they will go on and use that for first team value."