Midfield man Liam Sercombe set the ball rolling when he fired the Grecians in front against the run of play in the 34th minute
Then two quickfire second-half goals from the visitors really floored Scunthorpe.
Midfield man Arron Davies scored with a tremendous dipping 35-yard effort before setting up Sercombe to net his second of the afternoon two minutes later.
Substitute Sam Parkin then completed the scoring in the 90th minute after fierce second-half pressure from the home side had gone unrewarded.
"Football is a funny game. Some weeks it goes for you, some weeks it goes against you," confessed Tisdale.
"Scunthorpe are a good team and I am sure they will be disappointed with the result.
"I don't think 4-0 does them justice - but then that's football.
"They put us under a lot of pressure and the platform for our success was the way we defended against them in and around our own box.
"We really had to stay focused and disciplined and look to hit them on the break.
"We are quite good at playing like this.
"The pleasing thing for me was the way we responded from the home defeat against Hartlepool last week.
"But in just the same way we did not get too down after that result, we are not going to get too carried away after this.
"Our first two goals were both excellent finishes. We could see as soon as Arron struck his in the second half that it was going to be close.
"Scunthorpe changed things around after going 3-0 down and we decided to defend the edge of our box - but we knew that it would be a long last half hour and if they got one back, they might quickly get another."
- Sports & Recreation
- Arron Davies