Editor’s Note: David Gergen is a senior political analyst for CNN and has been an adviser to four presidents. A graduate of Harvard Law School, he is a professor of public service and director of the Center for Public Leadership at Harvard University’s Kennedy School of Government. Follow him on Twitter.

Story highlights

David Gergen: Americans felt strongly Obama would win, but they scored Romney the winner

Romney drove the debate, with a coherent message hammering at jobs issue, Gergen says

He says Obama missed one opportunity after another to go after Romney effectively

Gergen: Incumbent presidents tend to suffer in first debate, then improve

CNN  — 

What an upset!

Before the first presidential debate, voters were telling CNN by nearly a 2-1 margin that they expected an Obama victory. Many commentators were ready to hold a coronation for the president. Now, by more than a 2-1 margin, voters who watched the debate are saying that Mitt Romney won it – and we have a horse race on our hands.

Opinion: Debate coach – Obama, heat up; Romney, stay cool

David Gergen

Romney was one of the two big surprises of the night. His performance was head and shoulders above anything he has displayed so far. He drove the debate, had a coherent message that focused on jobs, showed a superior command of detail, was empathetic toward people hurting, and looked the president in the eye. He came in hungry.

  • Did you miss the first presidential debate? You can watch the full event online on CNN.com.

    President Obama was the other surprise. He was unusually flat, failed to go after Romney on point after point (47%, Bain, corporations are people, etc., etc.), rarely looked Romney in the eye, and seemed annoyed.

    My hunch is that no one has talked to him like this since his election (except maybe Bibi Netanyahu), and he was shocked that Romney denied he had ever proposed a huge cut in taxes (which he has). The net result was that Obama seemed to withdraw emotionally just when he should have launched a counteroffensive.

    Opinion: Romney wasn’t stellar, but Obama fell short

    We won’t know until the dust settles whether Romney has truly shaken up the race. After all, John Kerry as challenger beat President George W. Bush in debates and lost the election.

    In this case, Democrats are already charging foul against Romney for misstating facts. More to the point, we know from the past that incumbent presidents often come into a first debate a little complacent, lose, and then come roaring back in a second encounter (think Reagan 1984). Obama is highly competitive and will surely be loaded for bear next time.

    But the first night goes down as a big upset for Romney – and it is now more likely that this race will go down to the wire.

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    The opinions expressed in this commentary are solely those of David Gergen.