(CNN) Julián Castro walked onto the debate stage in Miami on Wednesday night as a longshot candidate with a fat resume but stubbornly low poll numbers.

He also had his best night of fundraising on Wednesday and overnight into Thursday, his campaign spokesman told CNN, further proof that his debate performance gave him a boost. Two hours later, as the cameras dimmed on the first Democratic debate of the 2020 presidential election , the former Housing and Urban Development secretary was a Twitter trend of his own after delivering an emotional response to the immigrant crisis on the US-Mexico border and using his policy chops to sharply attack the better-known Texan in the race, former Rep. Beto O'Rourke.He also had his best night of fundraising on Wednesday and overnight into Thursday, his campaign spokesman told CNN, further proof that his debate performance gave him a boost.

The former San Antonio, Texas, mayor and the grandson of a Mexican immigrant drew cheers when he called for the passage of the Equal Rights Amendment. He flashed anger at the Trump administration's immigration policies, calling the drowning deaths this week in the Rio Grande of Oscar Alberto Martinez and his 23-month-old daughter, Valeria, "heartbreaking" but also a tragedy "that should piss us all off."

"Well, clearly I had a great night," Castro said on Thursday to CNN's John Berman on "New Day."

"Last night, people saw that I have strong track record of getting things done. I have the right experience. I have a strong vision for the future of the country. And as you played the clip there, people want to know can you stand up to Donald Trump? Can you handle yourself? Can you hold your own? And I more than held my own last night."

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