He sent a text message to his friend which said: "Kiko probably has quite a lot of money in her car. Her family is also very rich. May consider it. Furthermore, I know her pin.''
Crown prosecutor Aaron Perkins said Yu and Yongxin Li met with Kiko Li in the early hours of May 19 on the pretence of giving her a driving lesson.
He said CCTV footage of Kiko Li's car shortly before she was killed showed Yu driving, Kiko Li in the front seat and Yongxin Li sitting behind her.
She was found with 22 wounds, one of which went into her heart.
Her body was found in the boot of her abandoned car in Hamilton.
Mr Perkins said Kiko Li was only 1.52m tall and weighed 45kg but she had knife wounds on her arms, hands and fingers which indicated she fought back.
"She of course had no chance.''
He said the Crown case was that Yu stabbed Kiko Li or encouraged or helped his friend Yongxin Li do it.
Yu's lawyer Mark Edgar urged the jury to keep in mind the possibility that his client had changed his mind about the killing.
He pointed to another text message from his client days before the killing which said: "I've obtained $2000. Put our plan on hold.''
Mr Edgar asked the jury to consider whether Yu knew Yongxin Li had a knife in the car.
Mr Perkins told the court that CCTV footage showed Yu trying to use Kiko Li's eftpos card twice. He did not know the 18-year-old's pin number and the card was "swallowed up.''
"Ms Li died for what could only be a modest amount of money but in actual fact, she died for absolutely nothing.''
About a week later, Yu and a third man drove Kiko Li's car to Hamilton and left it there.
Mr Perkins said Yu was interviewed by police in the days following Kiko Li's disappearance.
Police by this stage had the bank CCTV footage and asked if Yu knew what happened to Kiko Li.
Yu replied: "I don't know sorry. I really want to find out and I'm trying my best to help you.''
When it was put to him that he tried to use Kiko Li's bank card, Yu's response was "prove it''.
The trial is set down for three weeks and will hear from 44 witnesses.
Li has pleaded guilty to his part in the murder and was sentenced in May to life in prison with a minimum non-parole period of 16 years.
