NASCAR great Michael Stefanik was killed Sunday while piloting a single-seat plane that crashed in Connecticut, authorities said.

The 61-year-old stock car champion took off in the single-engine Aerolite 103 from Riconn Airport in Rhode Island and had tried to return to the airfield when the plane crashed near the state border, according to Connecticut state police.

Allen Sayles, who lives near the airport, said he saw the aircraft flying close to the treetops in a cloud of “big powerful smoke” before hearing an explosion around 2 p.m., according to news station WJAR.

His grandson and the boy’s father rushed to the scene and witnessed Stefanik walking near the wreckage.

“They said he was walking and he was talking,” Sayles told the outlet. “He was out of the plane. He was like 15 feet from the plane.”

Stefanik, who lived in Rhode Island, was brought with severe injuries and burns to a hospital, where he later succumbed to his injuries, NBC Connecticut reported.

The cause of the crash is under investigation, police said.

NASCAR confirmed Stefanik died in the crash.

“Mike Stefanik was one of the most successful drivers in NASCAR history, but even more so, he was a true representative of our sport,” NASCAR chairman and CEO Jim France said in a statement. “His tough, competitive nature and excellence on the race track won him the admiration of fans and competitors alike.”

Stefanik holds the Whelen Modified Tour record with 74 victories between 1985 and 2014. He had won nine NASCAR series championships, which tied him with Hall of Famer Richie Evans.

He was remembered Sunday by fellow NASCAR driver Dale Earnhardt Jr., who survived a fiery plane crash last month in Tennessee.

“Breaks my heart,” Earnhardt Jr. tweeted. “I hope his family and friends can find some peace and comfort somehow.”

Stefanik is survived by his wife, Juline, along with their two daughters, Nicole and Christine.

Nicole paid tribute to her father in a sweet Instagram post.

“My head hurts so much,” she wrote on Monday. “We truly lost a great person, husband, father, son and friend. I know you are in heaven flying around, looking over us.”

With Post wires