Dewhurst began the campaign in 2011 with just about everything a statewide candidate running in Texas could want: A strong fundraising apparatus and the ability to self-fund millions of dollars, widespread name identification,connections to the state's most influential pols, and the goodwill of the state's popular Republican governor.
Cruz, meanwhile, was simply a little-known former state solicitor general with an intriguing profile but a long way to go in a state with multiple expensive media markets that require millions of dollars to stay in the advertising game.
But with attention-grabbing speeches and media appearances, the underdog slowly began catching the attention of influential national conservative players, including South Carolina Republican Sen. Jim DeMint's PAC and the anti-tax Club For Growth, both of which opened up their wallets to support Cruz's campaign. Cruz also begun coalescing conservative grassroots support inside the state. His Cuban heritage, relative youth, and conservatism brought him comparisons to Sen. Marco Rubio (R-Fla.).
But Dewhurst was no Charlie Crist, the Republican and now independent Rubio defeated in his 2010 primary. That's what made Cruz's win so remarkable. Dewhurst didn't run a bad campaign, and while he had his share of critics on the right, he could hardly be called a liberal Republican. Cruz ran a better campaign and simply convinced voters he was more conservative.
It didn't hurt Cruz that a third candidate, self-funding former Dallas Mayor Tom Leppert, was in the Republican race as well, peeling votes away from Dewhurst. Cruz finished second to Dewhurst in the late May primary, but because the lieutenant governor received less than 50 percent of the vote, a late July runoff was triggered. Cruz won that race, even as Dewhurst went hard negative with brutal ads tying him to China.
Now, the question is what type of profile Cruz wants to craft for himself in the Senate. He's shown a willingness to be a sort of ambassador between conservative activists and Senate Republican leadership. He's joining the National Republican Senatorial Committee as a vice chair to incoming head Sen. Jerry Moran (R-Kan.), a role that will involve reaching out to conservative groups and activists in the hopes of fostering better harmony between the two sides in Republican primaries.
Elsewhere, there were other impressive candidate performances during this election. Here are a few deserving of honorable mention:
* John Barrow: The last white Democratic congressman from the deep south defied the odds to keep his job in 2012. Remarkably, Barrow won reelection by seven points -- more than he did in 2010 -- despite being drawn into a district that gave Sen. John McCain (R-Ariz.) 56 percent of the vote in the 2008 presidential race. Barrow's novel ad campaign helped propel him to victory against a less-then-stellar Republican opponent.
* Deb Fischer: Up until about the final two weeks of the Nebraska GOP Senate primary, it was difficult to find anyone outside of the state senator's hardest core supporters who thought she had much of a chance of becoming the Cornhusker State's next senator. Her rise is a reminder that one of the byproducts of intra-party civil wars can be an unexpected outcome. As Attorney General Jon Bruning (R) and his allies spent months in a brutal back-and-forth against state Treasurer Don Stenberg (R) and his backers, Fischer quietly snuck to the front of the pack as voters grew weary of the two statewide officeholders. She got a late boost from billionaire Joe Ricketts, which helped seal her upset in the primary. Fischer went on to defeat former senator Bob Kerrey (D) in November.
* Joe Donnelly: Considering Donnelly's lead in the polls during the final week of the Indiana Senate race, the congressman's Election Day victory wasn't an upset, at least based on where the Indiana Senate race was down the stretch. But rewind to the beginning of the cycle, and you would have been hard pressed to find anybody who believed Democrats would pick up the Indiana Senate seat. Faced with a tough congressional map following redistricting, Donnelly decided to jump into the Senate race, in the hopes that conservative Richard Mourdock would knock off Sen. Richard Lugar in the Republican primary. Mourdock did, and Democrats felt they had a shot. But Donnelly still looked like an underdog in an increasingly Republican state that President Obama was not going to win a second time. He held his ground though, running a solid campaign based around underscoring moderate credentials and his support for the auto bailout. Mourdock doomed his own chances with a controversial October comment about rape.
* Jim Matheson: Running in a conservative district against one of the highest-profile Republican challengers in the country, polls showed the Utah Democratic congressman trailing during the final two weeks of the campaign. His opponent was Mia Love, who spoke at the Republican National Convention and was making a bid to become the first black Republican congresswoman. Matheson, whose name is well-known in the state (his father served as governor) proved to be the ultimate political survivor, defying both the polls and the conventional wisdom down the stretch in the contest.
* Kerry Bentivolio: Who would have thought two years ago that a reindeer farmer and former Santa Claus impersonator (yes, you read that correctly) would be joining Congress in 2013 in former Michigan Republican congressman Thad McCotter's place? That's exactly what's going to happen following McCotter's inability to get on the ballot and subsequent resignation from Congress, which was followed by a scramble for the seat that the Republican newcomer capitalized on. Bentivolio's public spat with his brother was one of many colorful stories in this campaign.
-- Aaron Blake and Chris Cillizza contributed to this post.