Having fallen to defeats to East Bengal and Sai Gon Xuan Thanh respectively in their campaign openers, both sides entered the clash at the Shah Alam Stadium desperately looking to avoid a second consecutive loss.
However, it was the Red Giants who drew first blood in the 8th minute when Francis Forkey Doe broke through and slipped the ball past the onrushing Sasa Dreven before firing into an unguarded net, but the visitors equalised 12 minutes later when Mustafic Fahrudin played a neat ball to pick out Aleksandar Duric inside the area; the 42-year-old making no mistake from close range.
A minute into the second half, Selangor found themselves ahead once more when Amri Yahyah found space on the edge of the area and curled home a sublime effort, only to again be pegged back three minutes later when Imran Sahib was left unmarked eight yards out and fired past an exposed Sharbinee Allawee Ramli.
The hosts then went ahead for a third time six minutes before the hour mark when Doe netted from the spot, after Amri had been barged over inside the area by Ismadi Mukhtar, but Tampines were not to be denied and forced the draw in the 71st minute when Kunihiro Yamashita met Shaiful Esah's corner and sent the ball into the back of the net with a firm header.
In the group's other game, Sai Gon Xuan Thanh and East Bengal played out a 0-0 draw at the Thong Nhat Stadium.
In Group G, Australian youngster Dimitri Petratos netted his first two goals for Malaysian treble champions Kelantan to fire them to a 3-1 away victory over Ayeyawady United of Myanmar.
Red Warriors captain Badhri Radzi fired his side ahead after just two minutes, before Petratos doubled their advantage eight minutes after the break.
Ayeyawady did manage to pull one back 11 minutes from time through a Dominik Bersnjak strike, but a minute later, Kelantan wrapped up the three points when Petratos was once again given all the time in the world to turn home a set-piece delivery.
The result means Bojan Hodak's men are now second in the group, two points ahead of Vietnam's SHB Da Nang, who beat Maldivian outfit Maziya 3-2 at the Galolhu National Stadium.
Despite ultimately ending on the losing side, it was the hosts who took the lead after 33 minutes when Asadhulla Abdulla raced onto a brilliant through-pass by Ibrahim Shiyam and lifted the ball over the onrushing Nguyen Thanh Binh, but Da Nang pulled level nine minutes into the second half when Danny Mrwanda struck with a left-footed volley from just outside the six-yard box.
The visitors then edged ahead in the 66th minute when Sebastian Merlo made his way into the area and fired into the bottom corner, but Maziya produced an equaliser of their own nine minutes from time when Thanh Binh failed to gather a pass from Shiyam, allowing Ahmed Nashid to fire into an unguarded net.
But in injury-time, Da Nang went on to claim all three points when Nguyen Minh Phuong lined up a 25-yard freekick and unleashed a terrific effort that swerved around the wall and into the corner.
Al Shorta moved three points clear at the top of Group D after beating Ravshan 2-0, taking the lead in the 53rd minute through Ali Ghalioum, before Qussai Habib added a second five minutes later.
Elsewhere in the group, Al Qadsia recorded an impressive 3-0 triumph over Al Ramtha at the King Abdullah Stadium.
Within the opening minute, the hosts took the lead when Mesaed Nada headed home a Bader Al Motawaa corner, and it was 2-0 a minute before the half-hour mark when Saleh Al Sheikh struck a powerful effort that opposition goalkeeper Abdallah Al Zubi was unable to prevent from crossing the line.
12 minutes from time, a convincing victory for Al Qadsia was wrapped up when Al Motawaa got in on the act, exchanging a one-two with Saif Al Hashan before lashing the ball into the back of the net.
Finally in Group C, Dhofar maintained their perfect start by picking up their second win of the campaign; a 1-0 triumph over Al Shab Ibb thanks to substitute Keoulen Lamah's injury-time header, while Al Faisaly got on the board by beating Duhok 1-0 after Tamer Haj Mohamad struck the only goal of the match at the death.
Wednesday's AFC Cup Results
Duhok 0-1 Al Faisaly
Dhofar 1-0 Al Shab Ibb
Al Shorta 2-0 Ravshan
Al Ramtha 0-3 Al Qadsia
Ayeyawady United 1-3 Kelantan
Maziya 2-3 SHB Da Nang
Saigon Xuan Thanh 0-0 East Bengal
Selangor 3-3 Tampines Rovers