When it took six seats out of only 30 races, most of which were not really seriously in contention. In fact even the Fox analysts indicated that only 7 seats were in contention. The Dems won 6 of those 7. That's a serious smackdown, even considering that 2 of those were immensely close, while others were just close, outcomes.
Notice that none of Republicans who lost by such razor thin margins, when control of the Senate was at stake, bothered to ask for a recount or otherwise contested the election. The Dems will do that in a race for the county weed control authority.
A dem down in Florida is still contesting his congressional loss. Whining about voters not being able to find his name on the electronic machine and that's why he lost. So he wants to be the winner because he assumes those not voting really intended to vote for him.