De Bruyne captained City on the night and led from the front, blasting in the opening goal after 17 minutes following a neat pass from Riyad Mahrez.
The 29-year-old was also involved in Foden's late winner.
"We know how special he is," he said. "He always finds the right pass at the right time.
"It's a relief, we had a lot of chances before that to put us way up. In the end I'm just happy to score and help the team in a crucial time for us.
"We're always confident and try to stay focused for the full 90. They're a great team so they'll have spells where they're going to have the ball, it's going to be a really interesting game [second-leg] and we have to stay focused for the full 90.
"As a team we're doing brilliantly, we're fighting for everything we can and we'll fight to the end."