The Glasgow winger had been in electric, early-season form, scoring five tries in the space of three games before tweaking a hamstring against Zebre in September.
After a frustrating two-month spell on the sidelines the 26-year-old has fought his way back into the Glasgow starting line up and – with a PRO12 strike rate of 20 tries from 39 outings – Van Der Merwe is determined to touch down again tonight.
He said: "It has taken a bit of time to get back to full match fitness after the hamstring problem, but I feel I am now very close to where I was before the injury.
"I was pleased with how I performed against Castres and now I am just really excited about running out against Edinburgh at Scotstoun.
"We have a great record against Edinburgh and obviously we are determined to retain the 1872 Cup and also pick up the double helping of PRO12 points that are up for grabs.
"Before the injury I was really flying and now I feel that my sharpness has come right back. The best way to make that point is to get back in among the tries tonight.
"It should be a special atmosphere at Scotstoun with the fourth stand up and what we have to do is give the fans something to really excite them and get them involved.
"Knowing how important beating Edinburgh is to the Glasgow fans, I have no doubt that a win tonight would be the best present we could give them for Christmas."
Skipper Al Kellock celebrates his new deal by returning to the second row alongside Tim Swinson after recovering from the arm injury that had him miss out at Castres. The preferred half-back partnership of Ruaridh Jackson and Niko Matawalu remains in harness.
There is just one personnel change to the back line which faced the Top 14 French side last week, with Peter Murchie taking the full-back position and Sean Maitland moving to the wing.
Up front, there are four changes from the trip to the Stade Pierre Antoine, with Chris Fusaro returning in at openside for the injured John Barclay. Rob Harley starts alongside Ryan Wilson in the backrow. Ryan Grant is in at loosehead with Pat MacArthur at hooker.
When it comes to pointing out the main danger posed by the men from the east, DTH not surprisingly plumps for flying Dutchman but now naturalised Scot, Tim Visser.
Van Der Merwe said: "Visser is a real threat no matter who he is playing against, as he showed in the Autumn Tests against the All Blacks.
"He just runs great lines and if you give him space to put the pedal down he is uncatchable.
"But we believe that our defence is good enough to keep him at bay and when you look at how close we came to beating Castres – despite the fact we were down to 13 men at one stage and played most of the second half with 14 men – then that underlines how good we are in that area.
"But there is a lot of frustration after the Castres game and the best way to get rid of that is to beat Edinburgh tonight.
"What we need is a win, that is the bottom line without any doubt. Despite the fact there were a lot of positives to take from the Castres game we still lost, so all that matters tonight is that Glasgow win."
Glasgow: Murchie, Maitland, Lamont, Horne, Van der Merwe, Jackson, Matawalu, Wilson, Fusaro, Harley, Swinson, Kellock, Low, MacArthur, Grant.