Stars have have won just one from three after successive losses to Melbourne Renegades and Sydney to sit sixth in the standings ahead of Saturday night’s clash with the Renegades in Melbourne.

The Stars looked strong for long periods against the Thunder but lost their way at the conclusion of both innings with the Thunder's Eoin Morgan smashing a last-ball six for the win.

Pietersen, who contributed 60 with the bat before sitting out fielding duties with a groin strain, said his side must learn to stay calm with the match in the balance.

“The team that panics first in T20 cricket loses,’” Pietersen said. 

“If we keep panicking, we’re not going to get anywhere this season, we’ve just got to put the panic away.” 

Pietersen said he would be fit for Saturday’s match against the Renegades.