Benedict, 82, wasn't hurt and delivered his traditional Christmas Day greetings in 65 languages from the loggia overlooking St. Peter's Square. While a bit unsteady at first, he also delivered a short speech about the world's trouble spots without problem.
The incident raised fresh questions about security for the pontiff, however, after officials said the woman involved. She even wore the same red-hooded sweat shirt.
Italian officials also remarked on the odd similarity of the breach to an assault two weeks ago on Premier Silvio Berlusconi by a man with a history of psychological problems. The attack in Milan broke the premier's nose and two teeth.
The Vatican identified the woman involved in Thursday night's incident as Susanna Maiolo, 25, a Swiss-Italian national with psychiatric problems who was immediately taken to a clinic for treatment. Efforts to obtain further details on Maiolo's background were unsuccessful, with Vatican and hospital officials citing privacy laws.
In the 2008 case, the woman never managed to reach the pope and was quietly tackled by security. During Thursday night's service, the pope's attacker launched herself over the barricade as Benedict processed down the aisle at the start of Christmas Eve service. As security guards wrestled her to the ground, she grabbed onto Benedict's vestments, bringing him down with her.
Virtually anyone can get into a papal Mass: Tickets are required but are easy to get if requested in advance. Identification cards are not necessary to gain entrance, although visitors must pass through a metal detector.
The Rev. Federico Lombardi said it's not realistic to think the Vatican can ensure 100 percent security for the pope considering he is regularly surrounded by tens of thousands of people for his weekly audiences, Masses, papal greetings and other events.
"It seems that they intervened at the earliest possible moment in a situation in which 'zero risk' cannot be achieved," he said.
The Vatican's security officials will nonetheless review the episode and "try to learn from experience," Lombardi told The Associated Press.
It was the first time a potential attacker has come into direct contact with Benedict during his nearly five-year papacy. Security analysts have frequently warned the pope is too exposed in his public appearances, but Lombardi noted that they are a necessary part of the job.
"People want to see him up close, and he's pleased to see them closely too," Lombardi said. "A zero risk doesn't seem realistic in a situation in which there's a direct rapport with the people."
While Benedict was unhurt in the fall, a retired Vatican diplomat, French Cardinal Roger Etchegaray, 87, fractured his hip in the commotion. He will be operated on in the coming days at Rome's Gemelli hospital, said Nicola Cerbino, a hospital spokesman.
Etchegaray, emeritus archbishop of Marseille who headed the Vatican's justice and peace and charity offices before retiring, was seen leaving the basilica in a wheelchair after the fall. Despite the fracture, his condition was "good," Lombardi said.
Rome Mayor Gianni Alemanno remarked on the "strange" coincidence in the recent security breaches, saying "We need in some way to be more vigilant over all, because in an open and globalized world, the number of unbalanced people and their aggressiveness can increase."
There have been other security breaches at the Vatican.
In 2007, during an open-air audience in St. Peter's Square, a mentally unstable German man jumped a security barrier and grabbed the back of the pope's open car before being swarmed by security guards.
Then there was the assassination attempt against Pope John Paul II by Turkish gunman Mehmet Ali Agca in 1981. John Paul suffered a severe abdominal wound as he rode in an open jeep at the start of his weekly audience in the Vatican piazza.
The pope is protected by a combination of Swiss Guards, Vatican police and Italian police. When he moves around St. Peter's Square during his weekly Wednesday audience, he does so in an uncovered white jeep; when he travels overseas or outside the Vatican, he usually uses one outfitted with bulletproof glass.
Since the Sept. 11, 2001 attacks on the U.S., the Vatican has tightened security at events where the pope is present. All visitors must pass by police to get into the square, with those entering the basilica going through metal detectors or being scanned by metal-detecting wands.
However, Sister Samira, an Indian aide to Vatican officials who attended the service and saw the incident, said she is never searched by security when she attends papal Masses, and said the same holds true for other people in religious garb.
Benedict has been remarkably healthy during his pontificate, keeping to a busy schedule and traveling around the world.
But in July, he broke his wrist during a late-night fall while vacationing in an Alpine chalet and had to have minor surgery and wear a cast for a month an episode that highlights the risk he ran in Thursday's tumble.
Benedict celebrated this year's Christmas Eve Mass two hours earlier than the usual midnight starting time in a move by the Vatican to ease the pontiff's busy holiday schedule.
His next major appearance is scheduled for Sunday, when he joins homeless people at a Rome soup kitchen for lunch. In addition, he is due to preside over a vespers service on Dec. 31, celebrate Mass on New Year's Day and another one to mark Epiphany on Jan. 6, and then baptize babies in the Sistine Chapel on Jan. 10.