The Scots squandered a glut of good rankings since they were defeated 18-11 at the penultimate game of this campaign.
That Murrayfield loss followed an error-strewn home overcome by Ireland and also a smallish screen against France at Paris.
“It’s tough being the team that puts the effort in every game and has close afterward can not pull it off,” Strauss said.
“That’s more frustrating. It was a good work but we need to have a better performance”
Scotland are with no multitude of important players, most especially captain John Barclay, full-back Stuart Hogg, wing Sean Maitland and centre Huw Jones.
Injuries to Tommy Seymour, Blair Kinghorn and try-scorer Darcy Graham meant Gregor Townsend’s side finished the game with scrum-half Ali Price on the wing and Flyhalf Adam Hastings at full-back.
“We’ve got plenty of injuries right now and a couple of new boys coming from. The notion is that there but we aren’t doing it and that’s soul searching,” Strauss told BBC Scotland.
“We’ve got to start looking at ourselves and determine what we may do . We’ve been doing this within the past four or three weeks but just been able to pull it off and that’s the frustrating point “
Graham crossed to the only score of the second half before Gareth Anscombe’s penalty killed the game with all the clock reddish.
Four things and pressing for a winning effort, Scotland earned several penalties from the Welsh 22 and Townsend was”very frustrated” referee Pascal Gauzere did not show a yellow card.
“We’d enough pressure from the second half to win,” said the head trainer, whose unwanted look to end their 36-year wait for a win over England at Twickenham next Saturday.
“Powerful defences will force errors but but we forced plenty of penalties out of Wales – I think five at the 22 that will normally lead to yelloWISh cards, but we have been very frustrated that didn’t happen.
“The players had to handle things that went against them – injuries and re-shuffling that the backline – but we revealed what we are made from at the second half at the Rugby we want to play and in our character”
Scotland’can not score at crucial occasions’ – investigation
Former Scotland and also British and Irish Lions prop Peter Wright on BBC Radio Scotland
Scotland were accurate at the second half, they created opportunities but, because it’s been this year they can not score at vital times. They’d enough pressure, territory and ownership at the second half to have scored a lot more than five points.