Cardiff - Wales coach Warren Gatland may be fond of saying his side have "forgotten how to lose" but assistant Shaun Edwards believes memories of a surprise defeat by Scotland two years ago will help guard against complacency when the Grand Slam-chasers return to Murrayfield on Saturday.

Wales, the only side left in this season's Six Nations who can complete a clean sweep with two rounds left, are on a great run of form.

Their 21-13 victory at home to England last time out saw Wales to a new national record of 12 successive wins.

They've lost just once in the Scottish capital in 12 years and another triumph this weekend would leave them just 80 minutes away from a Grand Slam when they welcome Ireland to Cardiff's Principality Stadium on March 16.

But memories of Wales's last match at Murrayfield are still vivid for assistant coach and defence specialist Edwards.

Despite leading 13-9 at half-time, Wales then conceded 20 points without reply as Scotland won 29-13 in a remarkable rally.

Finn Russell, back in the Scotland squad after missing last month's defeat by France in Paris with concussion, was the home side's hero that day with the flyhalf kicking 19 points.

"We are fully aware that the last time we went up there, they definitely did a great job on us," Edwards told WRU (Welsh Rugby Union) TV.

"Finn Russell was absolutely outstanding that day. They controlled the second half, and we definitely got on the wrong side of the referee that day as well."

The former Great Britain rugby league international added: "So we are very determined to go up there and give a better account of ourselves than we did in the second half two years ago.

"It's a while since we have actually been three (wins) from three, but we are fully aware of Scotland's threat.

"A couple of their players have said they don't feel they have been at their best so far in the campaign, and we feel that we are still improving as well, so hopefully our best rugby is yet to come.

"We always want to improve, and we would like to think the longer we have the players, the better we get.

"They will probably challenge us ball in hand probably more than the three teams (France, Italy and England) we've had before.

"We are fully aware of the potency of their two half-backs (Greig Laidlaw and Russell) -- they are very experienced -- and the speed and class they've got on the outside."

Gatland, in his final Six Nations in charge of Wales before he steps down after this year's World Cup in Japan, is due to name his team on Thursday.

The New Zealander will have to make at least one change after lock Cory Hill was ruled out of the rest of the Championship as a result of the ankle injury he suffered during a try-scoring display against England.

Ospreys' Adam Beard is in line to replace Hill, with Scarlets forward Jake Ball providing second-row bench cover.