Stuart Holden's shot that struck the post was as close as either team came to a goal, but Cahill felt the hosts shaded the contest.
"It was a good opening game and we did well defensively, defending as a team and there were some good individual performances today too," he told the club's website.
"On another day we could have won and out of the two teams, if anyone deserved to win it, it was us. Their keeper made some good saves and we hit the post but unfortunately coudn't score.
"It was hard work to break them down and likewise it was hard work for them to break us down. I think the best chances fell to us and on another day we might have taken them.
"The opening game, you want to get off to a good start, especially a home game, and we've really stressed this season that we want to turn this place into a bit of a fortress. We've shown we are hard to beat and the most pleasing thing was the clean sheet."