Washington D.C. - The Senate on Thursday confirmed President Barack Obama's nominee to be U.S. ambassador to Mexico, clearing the way for the first woman to hold what is considered to be one of the country's most important diplomatic posts.

Roberta Jacobson was confirmed by voice vote 9 months after her nomination. Sen. Marco Rubio, R-Fla., had been blocking her confirmation, objecting to her role in negotiating the normalization of U.S. relations with Cuba. At the time he was seeking the Republican nomination for president.

Jacobson is the assistant secretary of state for Western Hemisphere affairs. That position gave her a prominent voice in leading talks with Havana on re-establishing diplomatic ties and embassies after more than five decades of antagonism.

Secretary of State John Kerry said the U.S. was sending "one of our finest diplomats to advance this important relationship."

"I have long relied on Roberta's wise counsel and good cheer, and I am confident that as ambassador, she will bring her extensive experience and judgment to this critical post," Kerry said in a statement.

Mexico's Foreign Relations department said Jacobson's confirmation "demonstrates the importance of a bilateral relationship which, given its maturity, transcends internal situations."

"Ambassador Jacobson will give a new impetus to our bilateral relations and will contribute to the consolidating anew institutional structure, lending more certainty and solidity to this relationship," the Foreign Relations department said in a statement.

Jacobson is a career diplomat who previously served as deputy chief of mission in Peru, director of the State Department's Office of Mexican Affairs and deputy assistant secretary for Canada, Mexico and NAFTA issues.

Obama selected Jacobson for the post last June and she was approved by the Senate Foreign Relations Committee nomination in early November by a vote of 12-7. Rubio voted against her in committee.

In February, Kerry chided Rubio for blocking Jacobson's nomination, saying the senator was punishing a highly qualified candidate who did nothing wrong.

"He's out there running for president. He has ample opportunity to make his case about the policy," Kerry said of Rubio before Rubio dropped out of the GOP nomination race. "But don't punish the country because you're angry about what happened."

Obama's previous nominee to be ambassador to Mexico, Maria Echaveste, withdrew from consideration in January 2015, citing a prolonged nomination process and the interests of her family. She had not received a confirmation hearing in the five months following her nomination.