The two made their European bows at the Veltins-Arena in the 2-0 defeat, with goalkeeper Wellenreuther impressing again and striker Platte hitting the crossbar in the second half.
While European champions Real appear on course to progress to the quarter-finals, Di Matteo was eager to take the positives.
"We played well, we held them off and stood firm. I think that their quality going forward is what made the difference. If you give Real Madrid room then they're dangerous," he explained.
"We had two debuts today. Timon Wellenreuther put in a good performance and dealt well with a lot of balls. Felix Platte came on and wasn't scared. It's unfortunate that his shot came back off the bar.
"I think that if both lads keep working then they'll have a good future with us."
Goals from Cristiano Ronaldo and Marcelo did the damage in Gelsenkirchen, although Schalke face an easier second leg than last year when they travelled to Madrid following a 6-1 first leg defeat.
Captain Benedikt Howedes is refusing to give up hope but acknowledged his side face a tough test.
"The situation going into the second leg isn't great but we’ll make a good account of ourselves," he added.
"We'll try to be compact at the back in Madrid too and be dangerous from set-pieces and on the counter.
"We’re not giving up yet and there have been a lot of footballing miracles in the past."
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