| Blaine Willenborg | |
| Birth Date: | 4 January 1960 |
| Birth Place: | Miami, Florida, U.S. |
| Plays: | Right-handed |
| Careerprizemoney: | $249,307 |
| Singlestitles: | 0 |
| Highestsinglesranking: | No. 50 (10 September 1984) |
| Frenchopenresult: | 2R (1985) |
| Wimbledonresult: | 1R (1984) |
| Usopenresult: | 2R (1980) |
| Doublestitles: | 7 |
| Highestdoublesranking: | No. 13 (18 April 1988) |
| Frenchopendoublesresult: | QF (1985, 1987, 1989) |
| Wimbledondoublesresult: | 1R (1984, 1989) |
| Usopendoublesresult: | QF (1988) |
| Medaltemplates-Expand: | yes |
Blaine Willenborg (born January 4, 1960) is a former professional tennis player from the United States.
Willenborg enjoyed most of his tennis success while playing doubles. During his career he won 7 doubles titles and finished runner-up an additional 9 times. He achieved a career-high doubles ranking of World No. 13 in 1988. His career high singles ranking was world No. 50, which he reached on September 9, 1984.
| Result | No. | Date | Tournament | Surface | Partner | Opponents | Score | |
|---|---|---|---|---|---|---|---|---|
| Loss | 1. | 1982 | South Orange, U.S. | Clay |  Jai DiLouie |  Raúl Ramírez Van Winitsky | 6–3, 4–6, 1–6 | |
| Loss | 2. | 1982 | Indianapolis, U.S. | Clay | Robbie Venter | Sherwood Stewart Ferdi Taygan | 4–6, 5–7 | |
| Win | 1. | 1983 | Geneva, Switzerland | Clay | Stanislav Birner |  Joakim Nyström Mats Wilander | 6–1, 2–6, 6–3 | |
| Loss | 3. | 1984 | Washington D.C., U.S. | Clay | Drew Gitlin | Pavel Složil Ferdi Taygan | 6–7, 1–6 | |
| Loss | 4. | 1984 | North Conway, U.S. | Clay |  Cássio Motta | Brian Gottfried Tomáš Šmíd | 4–6, 2–6 | |
| Win | 2. | 1984 | Palermo, Italy | Clay | Tomáš Šmíd |  Claudio Panatta Henrik Sundström | 6–7, 6–3, 6–0 | |
| Win | 3. | 1984 | Bordeaux, France | Clay | Pavel Složil |  Loïc Courteau Guy Forget | 6–1, 6–4 | |
| Loss | 5. | 1985 | Bordeaux, France | Clay | Libor Pimek |  David Felgate Steve Shaw | 4–6, 7–5, 4–6 | |
| Loss | 6. | 1986 | Bologna, Italy | Clay | Claudio Panatta | Paolo Canè Simone Colombo | 1–6, 2–6 | |
| Win | 4. | 1986 | Athens, Greece | Clay | Libor Pimek |  Carlos Di Laura Claudio Panatta | 5–7, 6–4, 6–2 | |
| Win | 5. | 1987 | Munich, Germany | Clay | Jim Pugh |  Sergio Casal Emilio Sánchez | 7–6, 4–6, 6–4 | |
| Loss | 7. | 1987 | Bologna, Italy | Clay | Claudio Panatta | Sergio Casal Emilio Sánchez | 3–6, 2–6 | |
| Win | 6. | 1987 | Indianapolis, U.S. | Clay |  Laurie Warder | Joakim Nyström Mats Wilander | 6–0, 6–3 | |
| Loss | 8. | 1987 | Washington D.C., U.S. | Hard | Laurie Warder | Gary Donnelly Peter Fleming | 2–6, 6–7 | |
| Loss | 9. | 1988 | Lyon, France | Carpet | Michael Mortensen | Brad Drewett Broderick Dyke | 6–3, 3–6, 4–6 | |
| Win | 7. | 1989 | Florence, Italy | Clay | Mike De Palmer | Pietro Pennisi Simone Restelli | 4–6, 6–4, 6–4 |