Most strategic fight

[Savvajin]

I'll go with Piccolo vs 17

 

[Animelover5487]

Goku vs Jackie Chun. A fight beemtween true equals but Chun won (and would have won on two separate occasions if the announcer wasn't biased) through his experience and variety of techniques.

 

[GSM123]

Not a single fight, but Vegeta was a beast on Namek. Only fights Zarbon and Dodoria when they’re alone, steals that one DB so Freeza will have to heal him, steals the DBs after he’s healed. And to close it off he defeated Zarbon by throwing sand in his eyes and playing mind games with him.

Not a good strategy, but Vegeta was also pretty smart vs 19 and 20. He lets himself get drained to rip off 19’s hands and then bluffs his way out of fighting 20.

Kuririn tends to have some good strategies in his fights too. I particularly like his fight with Goku in the 22nd Tenkaichi Budokai.

I don’t think Piccolo had any strategy vs 17. The androids showed up at Kame’s and Piccolo just said “fuck it we ball”. If anything he was dumb since it alerted Cell of where the androids were.

 

[SSJ2]

I'd second Goku vs Chun. To add to what Animelover said, the very nature of Chun's victory was based on a level of strategy that wouldn't have been effective unless both opponents were equals. Chun knew that the length of his limbs would give him the slightest advantage over Goku that was needed to put him down. That level of strategizing was never seen again.