Habib Diarra swept in Senegal's first goal mid way through the first-half at theSeattle Stadium.
The 22-year-old reacted fastest to slot the ball into the net past Belgium goalkeeper Thibaut Courtois after Ismaila Sarr's header bounced off the right hand post.
Sarr doubled the advantage early in the second half with a scorcher of a goal.
He controlled the ball from a long pass on his chest, let the ball bounce and lashed his shot past Courtois.
And Senegal controlled the game against a witless Belgium.
Victory five minutes away
But Senegal imploded with victory in their grasp.
Romelu Lukaku halved the deficit in the 86th minute with his 93rd international goal and Tielemans nodded in the equaliser three minutes later after Senegal goalkeeper Mory Diaw misjudged a cross.
The tie appeared to be heading for a penalty shootout when Lamine Camara clipped Tielemans in the penalty area as they both stretched for the ball.
Last hurrah: Senegal's Sadio Mané
Referee Said Martinez checked with his video assistants and pointed to the penalty spot.
Tielemans swept the penalty into the top left hand corner of Diaw's goal to send Belgium into a last 16 showdown with either hosts United States or Bosnia and Herzegovia.


Three arrested in Bolgatanga over alleged attempted baby sale for GH¢20,000, hum...
Ghanaian shot dead in South Africa as tensions over anti-immigration protests pe...
Accra Flood Disaster: Hajia Charity challenges Bawumia, demand accountability fr...
"I'll smoke them out!" – Kojo Bamba alleges powerful NPP figures plotting agains...
Two arrested after climbing Empire State Building antenna for marriage proposal
Fire breaks out in central Kyiv after explosion during air raid alert
US-Iran Doha talks end without breakthrough, focus on Strait of Hormuz
Venezuela death toll rises to 2,295, seven days of national mourning declared
Maritime insecurity costs West Africa over $500 million annually — Vice Admiral ...
Sahel insecurities threaten trade, investment and free movement in West Africa —...