Semi-finalists Entente Setif and Vita Club would be advised to steer clear of CAF Champions League record books ahead of the second leg matches this weekend.

Algerians Setif and Congo's Vita hold 2-1 leads going into away matches against Congolese TP Mazembe and Tunisians CS Sfaxien respectively.

But none of the seven previous teams who built 2-1 semi-final, first-leg advantages in the 49-year premier African club competition have gone on to reach the final.

Ivorians ASEC Mimosas, Togolese Lome 1, Senegal's Diaraf and Jeanne d'Arc, Cameroonians Canon Yaounde, Sudanese El-Hilal and Egyptians Al-Ahly have all failed down the years.

ASEC were the first club to discover a 2-1 lead is insufficient, crashing 4-1 away to Canon in the return match of a 1971 semi-final.

And Ahly were the most recent failures, but came closest to bucking the trend, losing 1-0 at Tunisians Esperance and exiting on the away-goal rule.

Lome, Diaraf, Canon and Hilal suffered one-goal overall defeats and ASEC and Jeanne d'Arc suffered two-goal losses.

Setif are lucky to even be in front having fallen behind just after half-time when conceding an own goal before a Sofiane Younes header and an Abdelmalik Ziaya thunderbolt rescued the 'Black Eagles'.

The Algerians make the long journey south to mining city Lubumbashi in the heart of central Africa boasting the only unbeaten Champions League record among the four survivors.

Leading scorer El-Hedi Belameiri has played a pivotal role with six goals, making him the joint leading scorer in the competition.

But four-time African champions Mazembe can also brag as they have won all five home matches with a 9-1 goal tally.

What the Congolese lack, though, is a consistent scorer with three-goal Tanzanian Mbwana Samata the lone attacker to make a significant impresssion.

Another key figure for Mazembe could be Robert Kidiaba, the pony-tailed 38-year-old goalkeeper who uses his bottom to bounce around the goalmouth whenever the 'Ravens' score.

He regularly defies his advancing years with breathtaking saves, but is also prone to commit howlers, like a fumbling first-leg attempt to prevent Younes levelling.

Sfaxien, alone among the semi-finalists in never having been African champions, were in trouble when Firmin Ndombe Mubele and Luvumbu Nzinga scored for Vita.

But the Tunisians clawed back one goal through Ali Maaloul and Imed Louati and Mohamed Ali Moncer wasted late chances to equalise.

They have an almost perfect home record with wins over Ethiopians Dedebit, Guineans Horoya, Libyans Al-Ahly Benghazi and Esperance before Setif forced a draw.

After qualifying defeats at Nigerians Kano Pillars and South Africa's Kaizer Chefs, Vita have grown increasingly assertive on the road and beat five-time African champions Zamalek in Egypt.

Should Mazembe and Sfaxien qualify for the final, it will be a repeat of the 2013 decider in the second-tier CAF Confederation Cup which the Tunisians won dramatically.

The late winner was snatched by Fakhreddine Ben Youssef, who scored in the first four Champions League games this season and has since gone 709 minutes without adding to his tally.