After a rain-interrupted opening week of practice for the May 25 race, there was a long line of cars ready to go when the first of four days of time trials began at noon with the top 11 positions in the 33-car field up for grabs.
Patrick, just two weeks past making history as the first woman to win an IndyCar race, set the early pace with a four-lap, 10-mile qualifying run averaging 225.197 mph on the famed Indianapolis Motor Speedway oval.
That drew a huge cheer from the crowd of about 40,000 at the sprawling speedway, the biggest spectator turnout for pole day in more than a decade.
Patrick set off a national "DanicaMania" in 2005 when she qualified fourth, the best starting position for a woman at Indy.
But Wheldon, the 2005 Indy winner, spoiled her storybook moment Saturday when he came out about 20 minutes later and did a four-lap average of 225.840, pushing Patrick to the middle of the tentative front row.
Patrick, who was doing an interview in the media center during Wheldon's run, just shook her head and smiled ruefully when Wheldon's speed was announced.
But if her team was willing to gamble, Patrick still had a chance at the pole, thanks to Indy's unique qualifying format.
Each car is allowed up to three qualifying attempts per day, so Patrick's Andretti Green Racing team had the option of withdrawing her first run and trying again, up to twice more, Saturday. Qualifying was scheduled to go until 6 p.m.
"I think there's some more (speed) left," Patrick said. "If we make some changes, we can go faster. We definitely are ready to do whatever we have to do to be the fastest car out there today."
Wheldon was pleased with his run and cautiously optimistic that he could remain on the pole. But, with the current rules, nothing was certain.
Asked if he might go out again if his speed was knocked back to second or third, the Englishman said, "The name on the sidepod of the car is Target Chip Ganasssi Racing. That's purely his decision. I'm a gambler but Chip is the boss."
One wild card remaining was two-time Indy winner Helio Castroneves, last year's pole-winner, who was hoping to give car owner Roger Penske his 15th Indy pole.
Team Penske president Tim Cindric had Castroneves' car pulled out of the qualifying line after the wind became gusty about an hour into the session.
Castroneves, going after his third Indy pole, was smiling when he walked back to the team garage to wait for better conditions later in the day.
"It's my birthday," said Castroneves, who turned 33 on Saturday. "They said I could do what I wanted to do. Then they said, 'Out, we're pulling you out.' Oh well, we'll get our chance later."
Scott Dixon, Wheldon's Ganassi teammate, was third in the early going at 225.178, followed by Penske's Ryan Briscoe at 224.833, Andretti Green's Tony Kanaan at 224.794, Vitor Meira of Panther Racing at 224.345, Marco Andretti of Andretti Green at 224.162, Ed Carpenter of Vision Racing at 223.835, Tomas Scheckter of Luczo Dragon Racing at 223.779, rookie Graham Rahal of Newman/Haas/Lanigan Racing at 223.355 and Davey Hamilton of Vision Racing at 223.387.
The 19-year-old Rahal, son of 1986 Indy winner Bobby Rahal, was the fastest of the drivers transitioning from the defunct Champ Car World Series into the recently unified IRL IndyCar Series.
Any of those qualified drivers were in danger of being bumped out of the tentative lineup by cars completing faster qualifying runs later Saturday.
By the time the initial qualifying line ended and the track was opened for practice, five drivers had qualified and then been bumped. That included rookies Mario Moraes, Will Power and Oriol Servia, all transitioning from Champ Car, as well as veteran Ryan Hunter-Reay. Rookie Hideki Mutoh initially was among the top 11, but his car failed inspection and his speed of 223.653 was disqualified, putting Hamilton back into the tentative lineup.
A.J. Foyt IV and Bruno Junqueira, another transition driver, both spun without hitting anything. Foyt was on a warmup lap, but Junqueira had just begun a qualifying attempt.
All of those drivers were eligible to take up to two more shots at qualifying in the first round.
Eleven more spots will be decided Sunday, with the final 11 positions to be determined in qualifying next Saturday. After that comes "Bump Day" next Sunday, the last chance for drivers to knock the slowest qualifiers out of the field.
With the entry list beefed up by the open-wheel unification, 32 cars took part in practice Saturday.
