DENVER, Colorado — By most accounts, Republican challenger Mitt Romney was the clear winner of Wednesday's first debate with President Barack Obama. Romney engaged the incumbent while Obama looked down at his lectern. The challenger was a more forceful debater while Obama appeared less than engaged.

Here are five things we learned on Wednesday

1. Romney wins by setting the tone

The crucial and tone-setting first 30 minutes of the debate belonged to Romney.

Romney appeared practiced, at ease, confident and fluent in all things Obama. He aggressively criticized the president's record while also outlining, however vaguely, his own ideas about taxes and the deficit. Obama -- his answers slow, dry and cautious -- looked shaky.

When the sparring turned to taxes -- an issue on which voters trust Obama over Romney, according to polls -- Romney played down legitimate questions about his tax plan and stressed again and again that he wants to reduce taxes on middle income families.

He seized on Vice President Joe Biden's latest verbal miscue about how the middle class has been "buried" by the policies of the last four years.

"Under the president's policies, middle-income Americans have been buried," Romney said. "They're just being crushed. Middle income Americans have seen their income come down by $4,300. This is a tax in and of itself. I'll call it the economy tax. It's been crushing."

Obama had a chance to brush his opponent back by hammering home the fact that Romney has been strikingly vague in explaining just how he would pay for an across the board 20% tax cut without cutting cherished tax deductions.

Instead, a lethargic Obama veered into a plodding, numbers-based criticism of Romney's tax plan that was a far cry from his campaign trail rallying cries about how Republicans favor the rich.

Obama's performance in the first part of the debate called to mind a segment on "The Daily Show" in the early days of the Obama administration, when Jon Stewart teased the newly burdened president's press conferences as boring and uninspiring -- a far cry from the inspirational figure of 2008.

Romney entered the encounter with Obama battered, weary and under fire from his fellow Republicans. At the end of the night, he stood on equal footing in a 90-minute debate with the president of the United States. That's a win.

2. Romney holds his own

It was the biggest question coming into this first showdown: Could Romney seem presidential standing next to the Obama?

The answer appears to be yes.

"He held his own against the president of the United States, and for a Republican challenger that's pretty good," commented CNN's Wolf Blitzer, chief anchor of the network's political coverage.

"Romney at least held his own on the big questions: On the economy and the role of government," added CNN Chief National Correspondent John King. "When you're the challenger and you at least hold your own with the president of the United States in the very first debate, you walk off the stage happy."

Romney's campaign was thrilled with its candidate's performance.

"If it was a boxing match, it would have been called," said Eric Fehrnstrom, a senior adviser to the former Massachusetts governor. "I've got to believe that the heels on the president's shoes are worn down from being back on them for 90 minutes."

As you can imagine, the Obama campaign saw the debate very differently.

"(Romney) was on defense all night long," said David Plouffe, a senior adviser to the president.

It appears debate watchers think Romney passed the test every challenger faces in trying to stand with an incumbent president. According to a CNN/ORC International poll conducted right after the session, 67% of debate watchers questioned said that Romney won. One in four said Obama was victorious.

3. Missed opportunities

Heading into the debate, there was a belief, an expectation that Obama would challenge Romney on the infamous 47% remark in an attempt to paint the former Massachusetts governor as a cold-hearted patrician with little empathy for the middle class and poor. If executed correctly, it could have put Romney on defense and changed the tenor of the debate.

Obama didn't do it, which turned out to be a major mistake.

Nor did the president question Romney on why he wouldn't release more details about his taxes. Another opportunity lost in an effort to try and portray Romney as being an out-of-touch elitist.

Obama's failure to take the fight to Romney and the challenger's ability to dictate the tone and speed of the debate helped Romney win.

The narrative heading into the evening was that Romney's campaign was listing and in serious need of a win. To Romney's credit, he never blamed his staff for problems that beset his campaign over the past few weeks and he was the one who righted the ship.

Romney made the case that he was in the race to help the middle class at the same time advocating a government that was more business friendly. Romney's repeated references to business -- particularly his pledge to help small businesses -- opened a door for Obama to bring in the former Massachusetts governor's time at Bain Capital. It was never brought up.

Romney's strong performance comes at a critical time as conservatives have been openly criticizing his campaign and poll numbers in key battleground states such as Ohio were trending toward Obama.

Romney played offense, while Obama was forced to play defense. With 33 days until Election Day -- you don't want to be on defense.

4. Body language matters

Sometimes how a candidate looks is more important than what he says.

That may have been the case in the first presidential debate, in which Romney often looked more at ease than Obama. When speaking, Romney often looked directly at Obama, while the president mainly looked at the moderator or the cameras when he was speaking. And Obama looked down quite often while Romney was speaking.

"The president could barely look at Mitt Romney, which was interesting. He really wouldn't engage with him, where as Romney would take the president on, on every issue." said CNN Chief Political Analyst Gloria Borger.

While Romney's body language seemed energetic, the president's body language was just the opposite. He seemed a bit irritated.

"I don't think anyone's ever spoken to him like that over the last four years. I think he found that not only surprising but offensive. It looked like he was angry at times," added CNN Senior Political Analyst David Gergen, who has advised both Democratic and Republican presidents.

While Romney took part in nearly 20 GOP primary debates this cycle, Obama has not participated in a debate in four years. And it showed.

"Participating in so many Republican primary debates helped Mitt Romney. He was, right from the beginning, more comfortable debating. The president was rusty as a debater. He hasn't done this in four years." King said.

Senior Obama campaign advisers disagreed, saying that it was Romney who appeared ill at ease.

"People at home saw (Romney) get testy, interrupt the moderator," Obama campaign deputy communications director Stephanie Cutter told CNN.

"My thought is that you're going to find that people watching at home thought he was quite testy," Plouffe added.

5. Chris Christie vindicated

New Jersey Gov. Chris Christie bothered the heck out of Romney-world last Sunday when he shirked the expectations game and stated flatly that the GOP nominee would deliver an earthquake of debate performance that would turn the presidential race "upside down."

Not on message in the slightest. But it turns out Christie might have been right.

In the post-debate spin room, the very same Romney backers who were hyper-cautious heading into Wednesday night's debate were suddenly sounding a lot like Christie.

"Chris Christie is quite the prognosticator," said Romney adviser Eric Fehrnstrom.

South Dakota Sen. John Thune said Romney assuaged the Republican concerns about his candidacy -- and then some.

"I think this was a make or break moment for the Romney campaign and he delivered," Thune told reporters. "This is a whole new ball game."

One high-ranking Romney adviser also acknowledged what no one on their team would admit prior the debate: That a poor showing Wednesday could have derailed Romney's candidacy.

"We needed a big performance and we got a big performance," the adviser told CNN. "There's a lot of relief right now."

After the debate concluded, Christie adviser Bill Palatucci made sure to plug his boss.

"Only Chris Christie had the guts to say what he really thought -- that Mitt would shine," Palatucci told CNN in an email.