Washington (CNN) Kentucky Democrat Amy McGrath raised $2.5 million in the first 24 hours since mounting a challenge to Senate Majority Leader Mitch McConnell, her campaign said Wednesday, a significant haul for a candidate who Democrats see as a strong contender in their quest to retake the US Senate next year.

McGrath faces long odds in unseating McConnell, a fundraising juggernaut himself, and despite outraising her Republican opponent last year she was unable to get elected to the US House. But Wednesday's figures are nonetheless a sign of enthusiasm for her candidacy.

She received more than 69,000 individual donations online with an average contribution of $36, her campaign manager Mark Nickolas said.

McGrath's fundraising haul is more than that of retired NASA astronaut Mark Kelly , who raised more than $1 million in the first day after he announced his Democratic campaign for US Senate in Arizona.

McGrath's candidacy in the Kentucky Senate race marks a significant recruiting coup for Democrats.

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