TOPIC: Slam Dunk

What does 'slam dunk' mean in the following sentence?
She started the game with a slam-dunk!

“She started the game with a slam-dunk.”
Oxford's online dictionary defines this term as follows:
“slam-dunk verb [vn] (in basketball) to jump up and put the ball through the net with a lot of force
slam dunk noun”
The term originated in basketball, as a type of shot that is unstoppable (and thus almost guaranteed to produce a win for the team with good slam dunkers. The National Basketball Association (in the U.S.) holds an annual SlamDunk contest.
Now the term is often used in business and in newspapers to describe an action (or situation) that can easily accomplish its objectives, or, if used in the negative, to indicate that the action isn't so easily to accomplish. Following are two headlines using this term:
“Dana merger is no slamdunk” (=success of the merger is not guaranteed)
“Nissan's China venture was no slam-dunk deal” (=the deal wasn't easy to attain)