The phrase "already underestimated" is correct and usable in written English.
It can be used when discussing a situation or person that has been undervalued or not given enough credit prior to the current moment.
Example: "Despite his achievements, he has already underestimated the impact of his work on the community."
Alternatives: "previously undervalued" or "earlier misjudged".
Prediction: I've already underestimated the Wild.
I hear and see and know that you've already underestimated me and my nappy hair.
Other computer models have already underestimated how quickly cases would spread.
We have to fit in a lot today, I tell her at breakfast, though I have already underestimated how long it takes her to drink tea.
It doesn't hurt that Yahoo!'s search is already underestimated, but to catch up with Google, Yahoo! will have to do more than just offer a competitive product.
Ofri Cnaani's exhibition "Special Effects" asks, or perhaps dares: "Can you see a trick while it's happening?" If this question sounds simple, you've already underestimated her work.
Madrid had already grossly underestimated the problems at Bankia when it seized the mortgage lender last month after giving it a 4.5 billion euro cash infusion.
As domestic opponents have already discovered, underestimating Mr Ahmadinejad is tempting - and foolish.
Our esteemed football editor and his team of writers have already admitted underestimating Leicester, so we respectfully suggest that the 51% of readers who predicted that they would be relegated should follow their lead in the comments section below.
If Mr. Wolff envisioned this book ("written in the irresistible style that only an award-winning columnist for Vanity Fair can deliver," according to its jacket copy) as anything outside its subject's control, he underestimated his already larger-than-life subject's gifts as a control freak.
Some distances are strongly underestimated as already seen in Figure 5.
