diff --git a/src/equations/compressible_euler_quasi_1d.jl b/src/equations/compressible_euler_quasi_1d.jl
index 6844bf9bee5..9c7e3a7269b 100644
--- a/src/equations/compressible_euler_quasi_1d.jl
+++ b/src/equations/compressible_euler_quasi_1d.jl
@@ -314,10 +314,8 @@ end
 # 1D compressible Euler equations scaled by the channel width `a`.
 @inline function entropy(u, equations::CompressibleEulerEquationsQuasi1D)
     a_rho, a_rho_v1, a_e, a = u
-    q = a * entropy(SVector(a_rho, a_rho_v1, a_e) / a,
-                CompressibleEulerEquations1D(equations.gamma))
-
-    return SVector(q[1], q[2], q[3], a)
+    return a * entropy(SVector(a_rho, a_rho_v1, a_e) / a,
+                   CompressibleEulerEquations1D(equations.gamma))
 end
 
 # Convert conservative variables to entropy. The entropy variables for the 
diff --git a/test/test_tree_1d_euler.jl b/test/test_tree_1d_euler.jl
index 784d123128e..dc523586f89 100644
--- a/test/test_tree_1d_euler.jl
+++ b/test/test_tree_1d_euler.jl
@@ -409,6 +409,14 @@ end
     end
 end
 
+@trixi_testset "test_quasi_1D_entropy" begin
+    a = 0.9
+    u_1D = SVector(1.1, 0.2, 2.1)
+    u_quasi_1D = SVector(a * 1.1, a * 0.2, a * 2.1, a)
+    @test entropy(u_quasi_1D, CompressibleEulerEquationsQuasi1D(1.4)) ≈
+          a * entropy(u_1D, CompressibleEulerEquations1D(1.4))
+end
+
 @trixi_testset "elixir_euler_quasi_1d_source_terms.jl" begin
     @test_trixi_include(joinpath(EXAMPLES_DIR, "elixir_euler_quasi_1d_source_terms.jl"),
                         l2=[
@@ -423,6 +431,7 @@ end
                             1.821888865105592e-6,
                             1.1166012159335992e-7,
                         ])
+
     # Ensure that we do not have excessive memory allocations
     # (e.g., from type instabilities)
     let