The 33 year old finished the 135km punchy opener in the second group – four seconds adrift of stage winner Simon Gerrans (Orica-GreenEdge) – and sits 15sec behind the race leader in the overall standings.
Schleck suffered a mechanical at the base of the categorised Menglers Hill climb in what was an otherwise “OK” comeback.
“It was nicely controlled,” the Luxembourger said. “Towards the end it got very nervous because everybody was fresh and just waiting for that last climb.
“I stuck my front wheel in somebody else’s bike so I had to stop. I jumped on a bike and that’s when normally the chain falls off so I had to stop again and put the chain back on. I just chased the peloton back so not to lose any time.
“Of course you’re tired, of course you’re hurting and you’re telling yourself, ‘there you go, it does hurt,'” he continued. “But I’m good with that.”
Schleck said he trained throughout his suspension, which expired in July, and is happy with his shape having attended camps throughout pre-season.
“I would say it was good but let’s wait for the harder stages and see,” he said.
“As soon as I put a number on my back I want to win.”
Schleck served a backdated sanction after he tested positive for the banned diuretic Xipamide during the 2012 Tour de France. The Tour is again an objective for him, and brother, Andy, this year.
“It’s got to be our goal,” he said. “We’ve been second and third in the Tour and I think it’s fair enough to believe in another result, and that we can win it.
“First goal will be the Ardennes, have a break after that and then build up for the Tour.”