Pakistan, whose World Cup build-up was characteristically chaotic, beat joint hosts Sri Lanka by 11 runs following their opening victory over Kenya.
Another two points against Canada will go a long way towards ensuring their quarter-final place, but Afridi said his team must guard against complacency that had cost them dearly in the past.
\"If we think Canada is easier then I fear complacency might creep in, so we have to be at our best and carry on the good work,\" said Afridi.
The skipper has led from the front, taking nine wickets — the highest tally in the World Cup so far.
Afridi said the team were in high spirits after beating Sri Lanka on Saturday.
\"We had a very good win against Sri Lanka, but we still need to take every match seriously, more so against a team who we don’t know,\" said Afridi.
Pakistan have played Canada just once before in the World Cup, beating them by eight wickets in England in 1979.
\"We have tried to gather some video footage of their initial matches but we are not bothered about that. After this match, we have New Zealand so we must win this one and then think about future games,\" said Afridi.
Left-arm spinner Abdur Rehman will sit out the Canada match after suffering a muscle injury against Sri Lanka and is likely to be replaced by off-spinner Saeed Ajmal.
In-form batsman Misbahul Haq, who scored 65 and an unbeaten 83 in the first two matches, is likely to be rested after suffering a minor hamstring problem with Asad Shafiq expected to fill his place.
\"Some changes might happen for that game, but we still want to have such a combination where we give fast bowlers a chance as well. We can experiment with future games in mind,\" said Afridi.
Canada captain Ashish Bagai said he was deeply unhappy with his team’s performances in the first two matches.
\"Definitely we are very, very disappointed,\" said Bagai, after a 210-run loss against Sri Lanka and a 175-run mauling against Zimbabwe.
\"We had planned very well for the game against Zimbabwe but we were not up to it.\"
Bagai said his team needed to address its shortcomings.
\"We need to come back. Somehow it’s us as a batting unit that’s failing, that’s the most disappointing part. It’s our own mistakes which are going on again and again so we have no choice other than to figure out what’s going on.
\"It may be a lack of belief at the top order, that’s something for us to get sorted out very quickly otherwise we will be in trouble against Pakistan.\"
Canada were bowled out for just 122 and 123 in their two matches, with experienced opener John Davison failing to score in both.