Dreier will face off against Democratic nominee Russ Warner, who received 24,002 votes in his uncontested primary. Dreier earned 34,281 votes, while Butler had 12,850.
"[Dreier] is so well-entrenched that he isn't going to lose," Foothill Republican Assembly President Dave Wilcox said. "I am happy that he won resoundingly, and I expect to see him win the election."
Portantino, who received 21,457 votes in the primary, is seeking his third and final term. His Republican counterpart will be Alvaro Day, who was also uncontested in the primaries and accumulated 15,981 votes.
"I think it's going to be an interesting election," La Cañada Flintridge Republican Committee Chairman Al Restivo said. "I think he can give [Portantino] a run for his money."
La Cañada/La Crescenta Democratic Club President Dana Runge thinks an upset is unlikely.
"Portantino is a wonderful legislator who is very conscientious and hard-working," Runge said. "He is very concerned about his constituency, and as long as the voters know that, I think he is a shoo-in for reelection."
Portantino said he looks forward to meeting Day, but stressed his desire to continue to represent the "best district in California."
"I am looking forward to my final term to work on the things I care about, fiscal responsibility and more accountability for higher education," Portantino said.
He said this election was particularly special, as it was the first time his daughter, Sofia Portantino, who is attending UC Santa Barbara, was able to vote for him.
"She voted absentee and called me on the phone while she was filling it out," Anthony Portantino said. "It was fulfilling to have my 18-year-old daughter vote for me."