Background: Patients with R/R DLBCL ineligible for autologous stem cell transplant (ASCT) have a poor prognosis. In these patients, tafasitamab (anti-CD19 antibody) plus lenalidomide (LEN) has shown encouraging results in the open-label, single-arm, phase II L-MIND study (n = 81; NCT02399085). To evaluate the contribution of tafasitamab to the activity of this doublet, we conducted a global, real-world study of patients treated with LEN monotherapy (RE-MIND; NCT04150328). Here we present the primary analysis of a 1:1 patient-level matched comparison between the L-MIND and RE-MIND cohorts. Methods: Patients treated with LEN monotherapy for R/R DLBCL were enrolled in the observational, retrospective RE-MIND cohort. As in L-MIND, patients had 1–3 prior systemic therapies, including ≥1 CD20-targeting regimen; were aged ≥18 years; and were not eligible for ASCT. A 1:1 estimated propensity score (ePS) matching methodology ensured balancing of nine pre-specified baseline covariates. The primary analysis set, Matched Analysis Set 25 (MAS25), included patients who received a LEN starting dose of 25 mg/day. The primary endpoint was investigator-assessed best objective response rate (ORR). Key secondary endpoints included overall survival (OS) and complete response (CR) rate. Results: 490 patients were enrolled in RE-MIND across 58 centers in the US and Europe, of which 140 fulfilled the ePS matching criteria. The MAS25 included 76 patients each from the two cohorts. Baseline characteristics between cohorts were comparable. The primary endpoint was met with a significantly better ORR of 67.1% (95% CI: 55.4–77.5) for the L-MIND cohort versus 34.2% (95% CI: 23.7–46.0) for the RE-MIND cohort (odds ratio 3.89; 95% CI: 1.90–8.14; p < 0.0001). The CR rate was 39.5% (95% CI: 28.4–51.4) in the L-MIND cohort and 13.2% (95% CI: 6.5–22.9) in the RE-MIND cohort. A significant difference in OS favored the L-MIND cohort (HR = 0.499; 95% CI: 0.317–0.785). ORR and CR outcomes in the RE-MIND cohort were similar to the published literature for LEN monotherapy in R/R DLBCL. Conclusions: Significantly better ORR, CR and OS indicate potential synergistic effects of the tafasitamab + LEN combination in ASCT-ineligible R/R DLBCL. ePS-based 1:1 matching allows robust estimation of the treatment effect of tafasitamab when added to LEN. RE-MIND demonstrates the utility of real-world data in interpreting non-randomized trials. Clinical trial information: NCT04150328.