The Associated Press called the Senate race for Sinema on Monday night and McSally tweeted her congratulations to Sinema.
Ms Sinema's win achieves a long-held Democratic goal of making Arizona, with its growing Latino population, a competitive state. Sinema said that access to affordable health care was a topic that frequently came up when she spoke with voters, and that became a hard point for McSally who had to defend her vote, which was in line with the Trump administration, in support of the proposed Republican repeal of Obamacare. 42-year-old Sinema, a USA representative and former social worker, spoke to supporters on Monday night after the result was declared in her favour, saying: "It won't be easy and it won't happen overnight, but we can work together to meet the challenges our country faces".
Her almost single-issue campaign talked about the importance of healthcare and protections for people with pre-existing conditions. Ms. Sinema, a former social worker, narrowly beat by 1.7-% margin her Republican opponent Martha McSally, a former Air Force pilot and also a Congresswoman.
As the soon-to-be first Democratic Senator from Arizona since 1988, Sinema struck a noticeably bipartisan tone, highlighting McCain's commitment to compromise and serving country over party. Sinema was elected as a Democrat to the state legislature in 2004 and carved out a reputation as a liberal who could work with her conservative colleagues. Sinema previously made history as the first bisexual person elected to Congress, when she won a seat in the U.S. House in 2012.
Though Sinema wooed moderates, she needed liberals like Morrison in her corner for her win.
PHOENIX, AZ - Today, Kyrsten Sinema was elected to be one of the U.S. Senators for Arizona.
The Arizona Republic estimated 170,000 votes remained to be counted, mainly mail-in ballots that are counted in a labor-intensive process.
On Election Day, Sinema swung by Arizona State University's downtown Phoenix campus to hand out doughnuts and gleefully posed for photos.
Look for Arizona to become a battleground state in 2020.
Most of those - about 143,000 - are in Maricopa County where the numbers from the early ballots that are still being counted have so far broken Sinema's way.
"It was like they spent the weekend at the kitchen table" filling out the ballots in anger, Gallego said. She registered for the first time so she could vote for Democrats and against Trump. "But Arizona proved that there is a better way forward".
Planned Parenthood Action Fund mobilized its Arizona members to get out the vote as volunteers for Kyrsten Sinema and David Garcia.
Ron Horsford, a 50-year-old Republican, was at the same event and said he was excited to vote for Sinema. John McCain died. Republican Gov. Doug Ducey appointed Republican former Sen. Ms. Sinema takes the seat being vacated by Jeff Flake, a Republican who is leaving the Senate after repeated clashes with President Trump.Ms. Sinema's victory guarantees the Democrats at least 47 Senate seats.