The commanding performances came as the third round of qualifiers for the 2008 Nations Cup in Ghana kicked off with intense competition expected as only the 12 group winners are guaranteed places at the biennial tournament.
Perhaps the biggest surprise in Yaounde was that Barcelona superstar Samuel Eto'o, back in the starting line-up for four-time African champions Cameroon, did not feature among the scorers.
But Jules Nyongha, standing in after Dutch coach Arie Haan quit early this year, had nothing to worry about as Webo once again demonstrated his pedigree by scoring twice within 25 minutes of the kickoff.
His first was a soft tap-in and he eluded his Liberian 'minder' to snatch the second by connecting with a free kick from Geremi of English Premiership champions Chelsea.
Liberia, who beat Rwanda last October after losing their opening fixture in Equatorial Guinea, silenced the home crowd seven minutes before half-time when Greece-based Francis Doe reduced arrears with a soft goal.
Cameroon dominated the second half exchanges with desperate Liberia resorting to fouls and Dioh Wiliams was shown a yellow card for a clumsy challenge on three-time African Footballer of the Year Eto'o.
It got worse for Liberia when George Gebro was shown red after being cautioned twice and Idrissou Mohamadou, who plays his club football in Germany, settled the outcome by connecting with a Geremi cross.
Tunisia recalled midfielder Slim Benachour and defender Riadh Jaidi came out of retirement as the 'Carthage Eagles' shook off Group Four cobwebs from the early rounds to win with surprising ease.
Former Esperance star Jomaa opened the scoring with a shot from the edge of the penalty area after 18 minutes and Haykel Guemamdia wasted a chance to add a second before half-time.
A defensive blunder gifted Jomaa his second goal after 77 minutes and the hat-trick was completed soon after when a rapid counterattack caught the home defence napping.
Sibusiso Zuma had three chances to put South Africa ahead before striker Surprise Moriri claimed his first international goal and impressive midfielder Delron Buckley added a second in first half stoppage time.
Zuma finally hit the target with 14 minutes left, scoring from close range, and the match was marred in the closing stages when a missile struck a Benin assistant referee causing a five-minute delay.
Arsenal striker Emmanuel Adebayor scored twice as Togo welcomed back coach Stephen Keshi with a 3-1 win over Sierra Leone in Lome to move two points clear of Group 9 pacesetters Mali, who host Benin on Sunday.
Olufade Adekanmi was also on target for the Togolese, who fired former Nigeria star Keshi after disappointing results at the 2006 Nations Cup tournament in Egypt, and who also had a blazing row with Adebayor during the tournament where they had to be prevented by the other players and officials from coming to blows.