"I really won the lottery when I got through those exams." 
 Note: in this case, "really" is just used for emphasis, and not actually meaning that a person really did win a lottery.
"I pulled off a miracle when I got through those exams."
"I was fortunate through those exams."
If you were just a lucky guesser, "I guessed my way through those exams."
There is also the concept of verbing a noun. (Interestingly, the word "verb" refers to a type of word, which is a noun, so the word "verb" is a noun, so the phrase "verbing a noun" is an example of verbing a noun.) If you can think of any familiar examples, whether historical and global or even recent and local, of a lucky person or event, you could use a word that refers to a lucky person or event. For example, "I Stevened my way through those exams last week" might not be readily understood in general, but if the conversation was just discussing how Steven spectacularly pulled off a streak of luck in four different ways over the past few days, then associating Steven's name with the word "luck" could be understood to anyone familiar with the context.