Rosol thought the contact was intentional.
"I was surprised he could do it on the Centre Court at Wimbledon," Rosol said.
But the obscure Czech was not to be rattled. Nadal made his earliest Grand Slam exit since 2005, losing in the second round on Thursday, 6-7 (9), 6-4, 6-4, 2-6, 6-4.
"In the fifth set, he played more than unbelievable," Nadal said. "Before, first three sets, I didn't play well."
Nadal's demeanor grew glum as the match progressed, and in the third set, he bumped into Rosol as they crossed to reach their chairs for a break.
"He wanted to take my concentration," Rosol said. "That's OK. I knew he would try something, but I was concentrating."
The 26-year-old Rosol remained focused to the finish, earning the biggest win of his career while playing in Wimbledon's main draw for the first time. He lost each of the past five years in the first round of qualifying.
At No. 100, Rosol is the lowest-ranked player to beat Nadal in a Grand Slam tournament.
As the match stretched beyond dusk, the conclusion came with the retractable roof closed for the final set. The upset on tennis's biggest stage was no fluke: Rosol served brilliantly and repeatedly stepped inside the baseline to hit aggressive groundstrokes, while Nadal found himself pinned deep and on the defensive.
Among those shocked by the result was Rosol.
"I'm not just surprised; it's like a miracle for me," he said. "I never expected something like this."
Nadal saved three set points to win the opening set, but his mood soon became cross. Chasing a drop shot in the second, he stumbled into the net as his racket went flying to the sideline, and he rose frowning at the slick grass.
After falling behind in the third set, he grumbled to the chair umpire during a changeover, apparently irritated by Rosol's movements awaiting serves.
After the match, Nadal declined to say what had him annoyed.
"Anything that I will say now will sound against me," he said. "It's not the right moment for me to say what happened out there, because it's going to sound like an excuse."
Added Rosol: "I was concentrating on myself. I don't know what he was complaining about."
Rosol exhaled before hitting his final shot, which was his 22nd ace, then fell to his knees with his arms up and collapsed facedown on the famous grass. He rose and shook hands at the net with a frowning Nadal.
"I think I was better today a little bit," Rosol said.
The 6-foot-5, 178-pound Czech lost only 16 points on his first serve, cracked his returns into the corners and won 22 of 28 points at the net.
In short, it was a complete performance that had spectators wondering why they'd never heard of him before. Nadal lost despite committing just 16 unforced errors in 276 points.
The Spaniard had reached the final in the past five Grand Slam tournaments and had played in the final of his past five Wimbledons.
Rosol will next play Philipp Kohlschreiber.
Murray gave the home crowd at Centre Court a brief scare when he was broken in his first service game, but he held serve the rest of the way and broke Karlovic four times.
Murray, again carrying the hopes of the home nation looking for its first British man since Fred Perry in 1936 to win Wimbledon, reached the third round for the seventh straight year. He has reached the semifinals at the All England Club the past three years.
A day after Prince Charles made his first visit to Wimbledon since 1970, Murray's match was watched by Prince William's sister-in-law, Pippa Middleton, in the Royal Box.
Roddick hit 13 aces, lost serve once and won 25 points at the net. The three-time Wimbledon runner-up will next play No. 7-seeded David Ferrer.
Roddick has struggled much of the year and he's seeded only 30th. But he won his fifth grass-court title last week as a wild card at Eastbourne, and he has swept all six sets this week.
"The good patches and the bad patches are all between the ears," Roddick said. "I'm still enjoying myself on the tennis courts, so it's not for anybody else to say whether I can or can't play."
Also Thursday, Mardy Fish hung on to beat 173rd-ranked British wild card James Ward 6-3, 5-7, 6-4, 6-7 (3), 6-3 in more than four hours to reach the third round, the American's first tournament since a medical procedure on his heart.
The 10th-seeded Fish could have ended things much earlier, holding a match point at 5-3 in the fourth set. But Ward saved that with a cross-court forehand passing winner. Fish then served for the match, but made a series of errors, including pushing a backhand wide to get broken.
More mistakes from Fish followed in the tiebreaker, including a double fault to drop that set.
In the fifth, though, Fish broke to 5-3 after several unforced errors by Ward, then capped the match with a 131 mph service winner.
For Brian Baker, there were plenty of low points along the way back to tennis's biggest stages. None worse, perhaps, than waiting to have reconstructive surgery on his right elbow in February 2008.
"I knew it would be a year and a half before I got back. It actually took longer than that," Baker said. "Sitting in the operating room, I told myself I'm not going to keep on coming back, having surgery, prolong my 'career,' if I can call it that."
He can now. Baker, a 27-year-old from Nashville, Tenn., did come back -- and he is now in the third round at Wimbledon, his best showing at any Grand Slam tournament.
After missing majors for 6½ years because of a series of operations, Baker returned to Grand Slam action last month by earning a wild card into the French Open, where he won one match. The 126th-ranked Baker followed that up by qualifying for Wimbledon, then winning two straight-set matches, including a 6-0, 6-2, 6-4 victory over 44th-ranked Jarkko Nieminen of Finland on Thursday.
"I was definitely not expecting to get through so easily," Baker said.
His comeback keeps getting better.
Baker was an up-and-comer who reached the French Open junior final as a teenager in 2003. But a couple of months after playing in the 2005 U.S. Open, Baker needed left hip surgery. That began a stretch of about 5#189; years in which he played in two low-tier tournaments -- and had five operations. That list includes a second left hip procedure, another on his right hip, a sports hernia repair, and the right elbow operation that's increasingly common among baseball pitchers and is known as Tommy John surgery.
That one required about three years for a full recovery.
While forced off the tour, Baker took classes and coached tennis at Belmont University in Nashville. All the while, he kept tabs on the up-and-coming players he'd faced as a kid, players who were around his age or a little younger, such as current No. 1 Novak Djokovic, Murray, Tomas Berdych and Jo-Wilfried Tsonga.
Djokovic owns five major titles so far; the other three all have been a runner-up at a Grand Slam tournament.
Tsonga of France overcame a sluggish start Thursday to beat Guillermo Garcia-Lopez in four sets and advance to the third round.
The fifth-seeded Tsonga, who defeated Roger Federer on his way to the semifinals at the All England Club last year, hit 40 winners in a 6-7 (3) 6-4 6-1 6-3 victory on Court 3.
Information from The Associated Press contributed to this report.