Lowes has this and probably HD or order from Sprinklerwarehouse.com

Looks like 3/4 so verify and get right size coupling and clamps

 

Can I use a PVC cutter to remove the damaged section or is there a better way?

 

That or razor knife. It will collapse but squeeze it round and the coupling will finish the job when inserting. I have never had to, but you may need to put pipe end in hot water to make it more flexible to insert coupling.

 

I fixed the leak with this this. Thanks for all your help!
How would you not use a sliding coupling, since the pipe does not give much?

 

I fixed the leak with this this. Thanks for all your help!
How would you not use a sliding coupling, since the pipe does not give much?
View attachment 26949

That's pretty cool, I've never seen a sliding coupling before. I've had to fix a few leaks like yours, I would usually either have to dig up a lot on both sides and try to get enough slack to get the coupling in place without kinking the tubing, or cut some from both sides and use two barb fittings and insert a new piece onto the two new barb fittings, a lot more work than that sliding coupling.

 

I have used the sliding couplings for PVC since they are buried nd don’t give. The poly I have runs 500 feet under pinestraw for azaleas so not an issue.