Le Roy's magic touch at the tournament has continued this year, with the 66-year-old reaching the knockout stages for the seventh time in eight attempts - achieving that feat with five different nations.
Congo qualified as Group A winners after Fabrice Ondama struck a late winner to consign Burkina Faso to a 2-1 defeat on Sunday.
The 61st-ranked nation also beat Gabon in the group stages and after their latest win, Le Roy struggled to contain his emotions.
He told Canal+: "It's incredible.
"I feel a lot of emotion and incredible happiness. These guys are incredible.
"We have come from nowhere. We knocked out Nigeria, the reigning champions [in qualifying].
"And now we have beaten Burkina Faso, who were runners-up last time.
"Anything that happens from now on is a bonus."
Almeria forward Thievy Bifouma has scored two of Congo's four goals in Equatorial Guinea..
A semi-final meeting against either Ivory Coast or Ghana will be the reward for the winners in Bata this weekend.
DR Congo are ranked four places higher than their opponents by FIFA but have not won a match at the tournament so far.
Three draws were enough for DR Congo to qualify for the last eight, with Jeremy Bokila's 66th-minute effort ensuring they held Tunisia 1-1.
That saw them progress on goals scored - despite netting just two so far.
A repeat of the performance that saw them beat Ivory Coast 4-3 in October will be what coach Jean-Florent Ikwanga Ibenge will be expecting.
Bokila scored twice, including an 88th-minute winner, on that occasion.
The two sides last met in qualifying for this year's tournament - back in 2013. DR Congo won the first clash 2-1 before Congo hit back with a 1-0 triumph.
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