Nathan Jones cast a frustrated figure following Southampton's 1-0 defeat to Aston Villa at St Mary's Stadium on Saturday.
Saints showed positive signs during the 90, at one moment looking like they had taken the lead but for VAR to overturn James Ward-Prowse's second-half goal.
Ollie Watkins got the eventual winner on 77 minutes, bringing to an end Jones's side's three-match winning run.
"I couldn’t have gone any more aggressive yesterday in terms of set pieces and nailing certain bits down," detailed the manager, "We defended set plays well today for the majority today but it was one that cost us again and that’s really frustration because in general play we’re not getting carved open.
"From front to back we’re defending superbly well and limiting teams to very little. It’s just set plays and if we can master that we’ll keep more clean sheets and that will give us more wins.
"We gave the ball away too many times. Defensively we looked strong, we looked aggressive but then we gave the ball away and we weren’t potent. We didn’t use our solutions enough so that’s something we’ve got to do better.
"We’ve got to be better on all levels and we’ve got to make sure we’re picking up points. If we defend one set play better today then we pick up a point and then we go ‘okay another positive, another point.’"