Former Premier League forward Wahbi Khazri scored twice as Tunisia recovered from a controversial loss to Mali by hammering Mauritania 4-0 in Limbe on Sunday in the Africa Cup of Nations.
The matchday 2 result threw Group F wide open with Gambia and Mali on four points, after a 1-1 draw between them earlier, and Tunisia on three with one matchday to come.
Tunisia face Gambia and Mali meet Mauritania on Thursday with the top two finishers booking second-round places and the third-placed team possibly going through as well as one of the best four in that position.
Khazri, who joined then top-flight club Sunderland in 2016 and now plays with French Ligue 1 side Saint-Etienne, scored in each half and created another goal for Seifeddine Jaziri.
The outcome was predictable as Tunisia are 73 places above Mauritania in the world rankings and kicked off having won 12 of the 16 previous matches between them with the other four drawn.
When the countries clashed at the Arab Cup in Qatar last month, Tunisia romped to a 5-1 victory without their unavailable Europe-based stars.
Tunisia lost to Mali in matchday 1 after Zambian referee Janny Sikazwe blew for full time although there were 13 seconds of regular time and unannounced added time to play.
The 1-0 score stood as Tunisia refused to return to the pitch and resume the match, saying the players were in ice baths.
Tunisia went ahead after just four minutes in difficult conditions at the Stade Omnisport with the temperature 32 degrees Celsius (90 Fahrenheit) and the humidity 77 percent.
Mauritania failed to clear a cross and the ball ran loose just inside the box to Hamza Mathlouthi, who hammered it across goalkeeper Boubacar Diop and into the far corner.
Rattled after conceding so early, the Mauritanians fell further behind on nine minutes when Khazri had ample time and space to score with a low shot from close range.
Mauritania could have reduced arrears midway through the opening half when Tunisia goalkeeper Bechir Ben Said lost control of the ball after a free-kick, but Oumar Camara failed to take advantage.
The Tunisians retained the two-goal lead until half-time and then scored twice within two minutes midway through the second half to put the outcome beyond doubt.
Khazri scored again after an Ali Maaloul cross and an exchange of passes with Ghaylen Chaleli created an opening and the captain slammed the ball into the net.
He then turned provided with a perfect pass setting up Jaziri to race through the middle and push the ball wide of Diop and into the net.
Tunisia wasted a chance to score again in the final minute of regular time when a Youssef Msakni penalty rebounded off the post.