The Democratic Senatorial Campaign Committee had its best fundraising month of the midterm election cycle so far in March, bringing in $8.1 million and outpacing Republicans, who raised short of $6.4 million for Senate races during the same period.

Strong fundraising at the committee level is crucial for Democrats, who have already faced tens of millions of dollars-worth of attack ads by pro-Republican outside groups such as Americans For Prosperity, helmed by the billionaire brothers Charles and David Koch. In a statement Wednesday, DSCC Executive Director Guy Cecil noted that "the Koch Brothers are pouring unprecedented millions into false attack ads aimed at boosting ... Republicans."

"But Democrats have a strong grassroots network and thousands of generous donors across the country helping us raise the resources we need to fight back," Cecil continued. "We need our supporters who care about having a Senate that fights for the middle class to continue to help us win each month and fund the grassroots operations we need to win."

One of the most ambitious projects the DSCC will aim to fund in a bid to hold its Senate majority is a $60 million investment in field operations across as many as ten states, which the committee hopes will be driven by thousands of staff on the ground and robust data operations. The project, if fully funded this election cycle, would approximately triple what the committee spent on field operations in 2012.

The DSCC has actively touted the project, which it calls the Bannock Street Project, to donors in a bid to attract more cash. But the committee was also boosted in March by multiple fundraising events featuring President Obama, who has remained a reliable draw for donors even as his public popularity and job approval have stagnated.

The DSCC finished the month with $22.2 million and having eliminated its debt; the NRSC, meanwhile, finished March with nearly $15.9 million on hand and also without debt.