Cushing's side dominated possession and created numerous clear-cut chances throughout the game but left it late on to secure all three points when Jennifer Beattie headed home a 93rd minute winner.
Claire Emslie also got her name on the score sheet in the 2-1 victory over Liverpool as City fought to maintain the pressure on FA Women's Super League leaders Arsenal.
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With Chelsea only drawing at home to West Ham, City's win meant the Blues were assured of a top-two finish, securing our place in next season's Champ;ins League.
And Cushing said that the knowledge his side will be playing European football again next term was exciting for everyone.
"I'm really pleased. I love the Champions League. We're really proud that we got to two semi-finals but we want to show progress," Cushing declared.
"We're also really disappointed with how it went this season and for our fans; evolving this team into being a team that people love watching and the Champions League is going to be a huge part of that.
"Getting back into the Champions League is great and whoever we get in the first round, second round and so on we've got to make sure that we get through to that semi-final and really push on because the team and the players have a huge desire to well in the competition."
The Blues boss also spoke of his relief when Beattie finally notched home the winner.
"We missed a lot chances in the second half but I'm really pleased that we went on and got the winner. In the 93rd minute all you want is for it to go in the goal, I don't really care how it goes in," the boss declared.
"It's (the title) out of our control but for us there will always be something to play for and that's being undefeated."