Maradona's side slip down the table, Jazira held at Emirates and Baniyas defeat Sharjah.
Al Ain lifted by win over Al Wasl in Etisalat Cup
The Saudi international made a diagonal sprint behind the Wasl defence and was fed the ball by Mirel Radoi, the Romanian midfielder.
Al Qahtani unleashed a heavy shot from the corner of the area, sending it past the advancing Ahmed Mahmoud.
Each side had a man sent off, and Al Ain's coach, the Romanian Cosmin Olaroiu, was removed from the dug out and sent to the stand after remonstrating with the referee in the moments following Al Qahtani's goal. Al Ain's victory avenged a 1-0 loss away to Wasl last weekend and lifted them past the Dubai club and into second place in Group A.
Al Ain went down to 10 men in the 22nd minute when Musallem Fayez was shown a straight red for a dangerous tackle from behind on Mariano Donda, Wasl's Argentine playmaker.
Wasl were unable to take advantage of their advantage, however, and they went down to 10 in the 62nd minute when Edson Puch, the Chilean midfielder, was sent off after planting the studs of his right boot on the calf of Al Ain's Abdulaziz Fayez.
Wasl pressed steadily for an equaliser, and only an acrobatic save by Walid Salem from a powerful shot by Essa Ali from 25 yards kept the ball from sailing just under the bar.
Four cautions were shown in the edgy match, and Al Ain fans were on their feet in the final stages.
Mohsine Moutaouali, the Moroccan midfielder, came on after 15 minutes to replace the injured 18-year-old Walid Anber and scored in the 42nd minute.
Jazira levelled in the 58th minute with Abdulraheem Jumaa connecting with a diving header from a Matias Delgado pass.
Emirates were reduced to 10 men in the 65th minute when Hareb Mohammed was shown his second caution of the match, but even with all four of their expatriates in the line-up, Jazira were unable to break down Emirates.
The hosts nearly won the game in the final minutes when Pejman Nouri, the Iranian, chipped a shot over the Jazira goaltender, Khalid Saif Al Sinani, but was ruled offside, albeit by a scant margin.
Yousuf Jaber scored in the 39th minute as Baniyas defeated strugglers Sharjah1-0.
Sharjah lost 4-0 to Baniyas away last week, and remain the only side in the cup competition without a victory.
Baniyas have won three consecutive matches, one in the league and two in the cup, since Salem Al Orafi, the Emirati, took over as interim coach after Jorvan Vieira was dismissed.
Baniyas played without David Trezeguet, as well as the playmaker, Amer Abdulrahman, who is on duty with the Olympic team.
Teams in the domestic flight return to Pro League play next weekend.
The Etisalat Cup resumes in February.