diff --git a/fmriprep/workflows/fieldmap/pepolar.py b/fmriprep/workflows/fieldmap/pepolar.py
index 32b870176..76b0b3962 100644
--- a/fmriprep/workflows/fieldmap/pepolar.py
+++ b/fmriprep/workflows/fieldmap/pepolar.py
@@ -139,10 +139,10 @@ def init_pepolar_unwarp_wf(bold_meta, epi_fmaps, omp_nthreads=1,
 
         workflow.connect([
             (inputnode, prepare_epi_matching_wf, [('in_reference_brain', 'inputnode.ref_brain')]),
-            (prepare_epi_matching_wf, qwarp, [('outputnode.out_file', 'source_file')]),
+            (prepare_epi_matching_wf, qwarp, [('outputnode.out_file', 'in_file')]),
         ])
     else:
-        workflow.connect([(inputnode, qwarp, [('in_reference_brain', 'source_file')])])
+        workflow.connect([(inputnode, qwarp, [('in_reference_brain', 'in_file')])])
 
     to_ants = pe.Node(niu.Function(function=_fix_hdr), name='to_ants',
                       mem_gb=0.01)