Sentence 1: Clara never beat her brother at Chess. 
 Sentence 3: Clara decided to practice Chess on the computer every day 
 Sentence 4:  When she beat the computer, she decided to replay her brother 
 Sentence 5:  Finally she was able to beat him! 
 Option 1: She was actually really good but didn't want to embarrass her brother by beating him. 
 Option 2: He was older and taught her to play, but she wanted to win once.