McCaskill said her supporters would be knocking on 35,000 doors on election eve.
"This is the exciting part of the campaign and the most gut wrenching part of the campaign, because this is it," she said.
"There's a slight advantage on Republican turn out, but not enough that's insurmountable,"
McCaskill admitted. "I'm fortunate that there are a lot of Republicans voting for me."
Across town, joined by Democratic secretary of state candidate Jason Kander, a Iraq veteran, Gov. Jay Nixon began the final before the election by touting his work on veterans issues.
At a breakfast stop in Columbia, the two touted the state's expanded "Show-Me Heroes" program, which Nixon established to help provide jobs to veterans who have returned home from serving.
"As Governor, I've worked with Republicans and Democrats to put the needs of veterans and military families first," he said. "By bringing people together, we'll continue to honor the service and sacrifice of these homegrown heroes."
Nixon praised Kander's service in the military - a key focus of his campaign as he challenges Republican Shane Schoeller for the open seat.
Nixon was scheduled to participate in an event discussing business issues in Springfield, before flying to Kansas City this evening for a rally with most of the statewide ticket.
Nixon's Republican rival, St. Louis businessman Dave Spence, was scheduled to embark on a statewide tour visiting Republican offices to encourage his supporters to get to the polls on election day.