Former Lions winger Jason Robinson said the tourists have been loose with very basic skills in attack but has backed crucial passes to stick against the All Blacks.
The Lions scored four penalties to one to beat the Crusaders 12-3 in Christchurch but any potential try-scoring chances went begging.
Robinson was renowned for his speed and ability to cross the line in both codes, and he believes the Lions must score tries and take the game to the All Blacks to beat them.
The Lions play the Highlanders in Dunedin on Tuesday in the first of three tour matches before the test series begins at Eden Park on June 24.
In The Sun Robinson, who won five Lions test caps across tours in 2001 and 2005, wrote: "The basics of the game are letting the Lions down in attack.
"They either play poor passes or force the ball in the red zone rather than take their time and recycle.
"In those situations it's important not to panic. You need to keep your composure and the space will eventually open up."
The Lions have scored two tries from three matches and conceded four - three to the Blues in their first tour defeat.
Robinson said the Lions had to convert pressure into points - something they failed to when dominating the Blues in the first half at Eden Park last Wednesday.
"Ireland beat the All Blacks last November by scoring tries and taking the game to them.
"The Lions are doing a lot of things right in attack and I'm convinced the tries will come.
"But they need to be more clinical because they won't get as many opportunities in the tests."
Following Tuesday's encounter in Dunedin, the Lions will travel to Rotorua to play the New Zealand Maori, before facing the Chiefs in Hamilton ahead of the test series.
Photo by: Getty Images (Liam Williams losing the ball as the Lions squander another attack).