I guess it would depend on the density of the imploded star, Thanos obviously went through one with far greater gravity than the one that Superman went through.
Not all stars are the same size after all, saying that Superman is greater than the Surfer is something many people just can't swallow, as they are nearly peers. Thanos crushed Supermans peer who is actually powerful enough to kill Superman due to powerset.
No Superman is not greater than Thanos thats a pipe dream. Thor is nearly an equal to Superman in strength, and Thanos took him with ease, and with the Power Gem, Thor took on a team without the Power Gem that would whoop on Despero.
Thanos beat Thor with the Power Gem and like I said Thor beat the Infinity Watch coupled with the Silver Sufer without the Power Gem.... Sorry Thanos wins this.