"That was very special and showed his potential.
"I wish Blake well, will keep in touch with him and follow his progress with interest."
Powell played 23 games for the Phoenix and scored eight goals.
The striker said he wanted to thank the club for being supportive of his decision to return home to Sydney to be closer to his family.
"I would also like to make a special thank you to Ernie Merrick for giving me a second chance in the Hyundai A-League and for his on-going coaching and support.
"Thank you to the supporters of the Phoenix for making me feel welcome in my first season, it was a pleasure getting to know some of you.
"Lastly, thank you to my team and the coaching staff for a great season. I have had the opportunity to meet some amazing people and I am very grateful for the time I spent with them all.
"I wish Wellington Phoenix the best of luck in the 2016/17 A-League season."