The Grecians dominated throughout and created the better chances in an entertaining game, but for all their endeavour they could not find a way past Gills goalkeeper Stuart Nelson.
Jamie Cureton missed three great chances for City, who lie four points off the automatic promotion places.
And Tisdale felt the gap could have been two points less. He said: "It was a very good performance and we gave it a really good go and I think we shaded the game.
"I think the players feel as though we deserved more. We've kept a clean sheet and took the league leaders right to the end of the game.
"We have had another player carried off (Matt Oakley) and we are being stretched to the limit with the squad again.
"We played really well and the players were not just committed, they really tried to do some good things and I would have backed Jamie Cureton to have made the goalkeeper work for at least one or two of the chances he had.
"We certainly played our game and I find it very hard to criticise the players because they gave it a really good go."
On the injury to Oakley, Tisdale added: "It looks a bad one. He has dislocated his shoulder and he is on his way to hospital to have it put back in.
"Losing him was a big blow for us, it stopped us in our tracks, but we continued to try and win and finished the game strongly."