The Frenchman - a regular in the Belgian national series - carried a comfortable 15.5sec into the penultimate leg but he was caught napping as championship leader Andreas Mikkelsen sliced that deficit to just 5.9sec after two stages.
Fearing for his position, Lefebvre saw red and found another gear in his Citroën C3 Rally2 - taking out stage wins on five of the six remaining stages to rebuild his advantage.
By close of play he was in an even better position than he had started in, ending 25.7sec clear of Mikkelsen’s Škoda Fabia Rally2 as well as being seventh in the overall standings.
“To be honest, we tried to push hard,” he admitted. “It was a tricky loop this morning but after that I felt more confident. We had a good afternoon loop and I am happy.”
Mid-leg set-up tweaks gave Yohan Rossel more confidence in his C3 and the Frenchman held position to end 39.0sec behind Mikkelsen in third. He was 21.2sec ahead of Hyundai i20 N Rally2 youngster Grégoire Munster, who led the WRC2 Junior category.
M-Sport Ford star Jari Huttunen retired his Fiesta overnight with engine troubles, leaving Chris Ingram to grab fifth in another Fabia machine.
Ingram trailed Munster by just 10.6sec but had almost one minute in hand over sixth-placed Vincent Verschueren, who was driving a Volkswagen Polo. Armin Kremer maintained his lead in the WRC2 Masters Cup after another solid day in his Fabia.
• Full coverage from Ypres Rally Belgium is available on WRC+ All Live here, including every stage broadcast as it happens as well as key interviews, features and expert analysis from the service park.
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