I found it on ITA, then oddly enough can't find it on orbitz which is where I typically go to lock in ITA deals. Regardless, found it on the qatar website, although when I select the SIN-ATH QR945 it prices at ~$1600 CAD, however QR943 comes out at the right price, as well as looking on expedia, both come out at the price found in ITA.
https://www.expedia.ca/Flight-Search...zDGTUqYNAI8tNB