Maro Itoje says the British & Irish Lions cannot afford to keep conceding penalties at the rate they have in the New Zealand tour to date.
The Lions edged past the All Blacks 24-21 in Wellington on Saturday to square their three-Test series at one win apiece.
Taulupe Faletau and Conor Murray claimed the tries with Owen Farrell blasting a late winning penalty, after Sonny Bill Williams was sent off for the hosts.
But they did so after conceding 13 penalties during the match, and Itoje, who was as guilty on that front as anyone in the Lions' Wellington win, has vowed to enforce a discipline clampdown before next weekend's series decider in Auckland.
"Thirteen penalties is way too many for us to be conceding," said Itoje. "It's something we spoke about and didn't fix.
"We will have to have a hard look at ourselves, figure out the reasons why we're giving away those penalties and try to reduce it.
"We've got to be more disciplined."
The Lions lost the first All Blacks Test 30-15 amid a battering in the pack from the hosts at Eden Park.
Boss Warren Gatland received the emotional and physical response he had demanded in the second Test, however, leaving Itoje proud of the Lions' riposte.
And the astute 22-year-old Saracens lock now believes the Lions can get even better, and all just in time for the series decider.
"We only got together six or seven weeks ago, and we've been improving week by week," said Itoje.
"The first couple of weeks it took us a bit of time to find our feet.
"Each day that passes is another opportunity to get to know the guys better, another opportunity to build that chemistry and another opportunity to improve and get a better understanding of one another.
"And I think that's what will happen."