diff --git a/unsupported/benchmarks/Tensor/bench_contraction.cpp b/unsupported/benchmarks/Tensor/bench_contraction.cpp
index 0b71ebfe3..faf648f6d 100644
--- a/unsupported/benchmarks/Tensor/bench_contraction.cpp
+++ b/unsupported/benchmarks/Tensor/bench_contraction.cpp
@@ -69,6 +69,9 @@ static void BM_Contraction_ThreadPool(benchmark::State& state) {
 }
 
 // --- Rank-3 batch contraction ---
+// Contracts A(batch, M, K) with B(batch, K, N) over batch dim (0<->0)
+// and K dim (2<->1), producing C(M, N). This sums over both the batch
+// and inner dimensions: C(m, n) = sum_b sum_k A(b, m, k) * B(b, k, n).
 static void BM_BatchContraction(benchmark::State& state) {
   const int batch = state.range(0);
   const int M = state.range(1);
@@ -77,12 +80,12 @@ static void BM_BatchContraction(benchmark::State& state) {
 
   Tensor<Scalar, 3> A(batch, M, K);
   Tensor<Scalar, 3> B(batch, K, N);
-  Tensor<Scalar, 3> C(batch, M, N);
+  Tensor<Scalar, 2> C(M, N);
   A.setRandom();
   B.setRandom();
 
   using ContractDims = Tensor<Scalar, 3>::DimensionPair;
-  Eigen::array<ContractDims, 1> contract_dims = {ContractDims(2, 1)};
+  Eigen::array<ContractDims, 2> contract_dims = {ContractDims(0, 0), ContractDims(2, 1)};
 
   for (auto _ : state) {
     C = A.contract(B, contract_dims);