Newcastle Jets coach Branko Culina has questioned the intestinal fortitude of his Sydney FC counterpart Vitezslav Lavicka.

The Czech tactician led the Sky Blues to the Championship/Premiership double in his first season in charge but has seen his magic touch wear off with the side now sitting at the bottom of the table.

Although Sydney have improved with a win (3-0 over Perth) and a draw (1-1 with league leaders Brisbane) in their past two matches, Jets boss Culina believes there are still testing times ahead for Sunday's rival.

"Lavicka is a lovely man and all of that, but coaches find their biggest test when things aren't going their way,'' Culina said yesterday. ''And I suppose Mr Lavicka hasn't been through the bad times yet.

"He's only been through the good times, and he handled it very well. The question for him, as a coach, is how will he handle the adversity?''

Newcastle are away at Sydney Football Stadium this Sunday, November 7 - kick-off is at 5:00pm.