"It just reminds you the margins are so slim," Herdman, who took over as coach in January 2018 after leading the Canadian women's team to consecutive Olympic bronze medals, said on a conference call on Thursday. "A penalty save, shots, crosses that could've, should've been converted.
"This game for us it will be no different. The margins as you get to these knockout quarter-final type stages are very slim and that level of concentration is going to be crucial."
Haiti used an impressive display of attacking soccer to rally from a first-half deficit to beat Costa Rica 2-1 and finish atop a Gold Cup group for the first time in seven appearances.
Herdman said that game offered him a good sense of what type strategy he expects to see from Haiti, a team he described as a cohesive group that are excellent in transition.
"They have so much athleticism and it's the speed at which they can send numbers forward and the commitment that goes behind them. I think Costa Rica were caught by that although they had a lot of good balls," said Herdman.
"For Canada it's definitely a red flag that we may possess quite a lot in this game but in those moments we lose the ball. We'll have to be on guard."
The Gold Cup, which consists of teams from North and Central America and the Caribbean, will ultimately serve as a barometer for how much progress the men's national team has made since Englishman Herdman took over.
After years of relative underachievement in the region, this version of the Canadian team are equal parts optimistic and determined to change the perception about what they are capable of achieving in tournament play.
"These players are very clear on what their mission is, to bring respect to our flag in the football world and to really step forward with a talented group," said Herdman.
"The pressure is already on in terms of internally what they want to achieve ... very clear that we have to step forward in this tournament as an opportunity to raise our flag higher."
(Reporting by Frank Pingue in Toronto, editing by Pritha Sarkar)
