McEwen claimed a ninth career stage victory by beating Boonen in a mass finish to the 228.5km stage from Obernai to Esch-sur-Alzette after a crash allowed Matthias Kessler to be caught in the closing stages.
Hushovd finished third to take the leader’s jersey from American George Hincapie after narrowly avoiding a high-speed crash when his left foot popped out of the pedal in the closing stages.
Boonen and Hushovd had earlier battled it out for intermediate sprint points and time bonuses on a long hot day to Luxembourg.
McEwen leads Hushovd and Boonen in the race for the sprinters’ green jersey.
“(Erik) Zabel and (Stuart) O’Grady went first and I didn’t want to leave it too late like yesterday and so I went for it,” McEwen said.
“At one point I clipped Hushovd with my feet but I just kept going. I felt great in the sprint and my team did an excellent job for me, as always.
“I have lost the green jersey twice in my career. This year I want to take it. Another stage is the priority, but I’m determined to take the green home.”
Hushovd, who needed five stitches after cutting his arm yards from the finish line on Sunday, leads Boonen by five seconds while the Belgian has an eight-second lead over McEwen at the top of the overall leaderboard.
The 137-mile route from Obernai in eastern France is the second-longest stage in this year’s race.
Spanish debutants Aitor Hernandez and David de la Fuente had staged a breakaway but were brought back in the later stages after riding over 150km together before De la Fuente broke clear on a solo run after his compatriot began to tire.
De la Fuente was rewarded for his efforts by picking up the King of the Mountains’ polka dot jersey after a hard day spent on the sweltering roads of eastern France.
An action-packed finish saw a peloton pile-up one kilometre from the finish after T-Mobile veteran Kessler had sent the pack racing for the finish at full speed when a touching of wheels split the pack in dramatic fashion with the end in sight.
Zabel (Milram) and O’Grady (CSC) set up a spectacular sprint after avoiding the crash but it was McEwen who took full advantage, although he almost sent Hushovd spiralling when avoiding Zabel on his right. Boonen peeled down the left but could only take second, with a battered Hushovd third.