"I ran in thinking she would drop-shot, and she didn't drop-shot, " Stosur said.
This time, Murray took his chance, chasing down a drop shot and steering a winner to seal the opening set.
Federer then dominated the tie-break, a forehand return and a drop shot helping him win five of the last six points.
Murray closed to 3-2 after winning a 25-shot rally with a backhand sliced drop shot, but he double faulted on the next point and Djokovic took full advantage.
Murray was targeting the 27-year-old's second delivery with huge success and he brilliantly chased down a drop shot to earn another break point, which was converted for a 4-1 lead.
Cypriot Baghdatis, finalist at the 2006 Australian Open, failed to find his rhythm against the unseeded Dutchman who used his height advantage, a stunning forehand and drop shot to great effect.
As well as strength, Sharapova's quickness of feet was a feature of an impressive performance, notably when she sprinted to reach an Errani drop shot, winning the point to take a 4-1 lead.
But the Briton took the next four points, gaining a crucial one on the Frenchman's serve when he was quick to react to a drop shot and steer a forehand winner cross court.
He wasted a match point in game seven by hitting a forehand into the net, but eventually ended his opponent's challenge after one hour and 21 minutes on court with a neat drop shot.
The German, an Australian Open finalist in 2003, earned his first two break points at 1-1 and snatched the second when he chased down a drop shot and whipped it back past a stranded Nadal.
Baghdatis had nothing left to offer and Murray broke serve once again with a deft drop shot on match point to move within one win of matching last year's run to the quarter-finals at Roland Garros.
Murray was hitting the ball cleanly and confidently, and when Federer wasted a chance to get the break back in game three with a poor forehand drop shot, the unusually frustrated reaction from the Swiss said it all.
BBC: Andy Murray beats Roger Federer to win Shanghai Masters
He had the Liverpool crowd on their feet with two breaks of serve in the third set but his comeback was snuffed out when Przysiezny broke back to cut the deficit to 4-3 with a beautifully judged drop shot.
Although there were times when the three-time Australian Open champion could only stand and watch the aces go by or send a drop shot return into the net, he largely had an answer for everything Roddick could send his way.
They were tied at 4-4 before a rain break disrupted play for 45 minutes and although both pairs looked strong on the resumption, Jeremiasz sealed the first set with a delicate backhand drop shot which just crept over the net.
There was another twist in this strangest of matches when Wawrinka fired a forehand long in the following game to hand the break straight back, but a magnificent drop shot in game five helped the Swiss regain the advantage and this time he held on.
The set now back under his control, Murray closed it out with another break as he fired one brilliant winner down the line from deep behind the baseline, before racing in to collect a drop shot and whip a cross-court forehand past Federer on set point.
BBC: Andy Murray beats Roger Federer to win Shanghai Masters
Chela goes long on the next point before having a rustle around in his top drawer and pulling out perhaps the shot of the match, a magnificent drop-shot from about six feet behind the baseline.
Els wins the hole after Garcia lands his tee-shot in a ditch and is forced to drop a shot.
Westwood has yet to drop a shot to par after 36 holes with his usual consistent play backed up by fine putting.
But her last drop-shot attempt landed in the net, and Sharapova fell to her knees and covered her face in her hands.
The Scot won a cagey first set with a fine drop-shot before a very close second which Blake won on a tie-break.
That's a little lazy from Murray, dabbing an attempted drop-shot wide, but he then chases down a lob before punching home a backhand winner.
Knifed drop-shot from Murray on the back-hand side, but that's great scrambling from Chela to keep the game alive, yanking a backhand volley past the flailing Scot.
They were to drop on the spot he played that shot from, drop in the drop zone, or drop on a line between himself and the hole from where the ball last crossed the margin of the hazard.
FORBES: Tiger Woods' Penalty Should Have Been Assessed On The Spot Or Not At All
Els misses his eight-foot putt for par to drop his first shot of the day.
Sterne became the first player since Tiger Woods in 2002 to drop just one shot over 72 holes in a European Tour event when he cruised to a seven-stroke victory over Schwartzel at the Joburg Open, having led from the start.
"Pre-premiere chatter helps, but if that doesn't eventually translate into sizable ratings ... the traditional multi-camera manner in which the show is shot could drop in demand to the level of a cord phone, " he wrote.
Woods told reporters he stood "two yards" behind the spot of his errant shot before the drop.
Start one thing, then drop it when a better shot comes around.
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