@boc: Thanos never got blitzed by anybody. He pretty much walked through everybody he faced until Thor came back with Stormbreaker.
But that's besides the point. When the fight starts Thanos will already be making a fist since he'll be ready for the fight. Clark won't be able to close the distance fast enough to prevent Thanos from activating the space stone.
He got blitzed by Iron Man and Spiderman (the latter with the help of Doctor strange.) That's just off the top of my head. Superman is insanely faster than both of these characters. And the space stone (or any of the stones) are not instant. Despite it taking about a second to activate, it takes even longer to affect anything. It simply does not have the feats to support what you are saying.