| ATP Mnichov | 04/13 12:00 | 14 | [303] Alessandro Giannessi v Marc-Andrea Huesler [232] | 3-6,0-6 | |
| Challenger Sarasota | 04/09 15:00 | 25 | Alessandro Giannessi v Calvin Hemery | 4-6,6-2,2-6 | |
| Challenger Mexico City | 04/03 19:25 | 26 | [304] Aidan Mayo v Alessandro Giannessi [297] | 3-6,7-6,6-3 | |
| Challenger Mexico City | 04/01 21:45 | 25 | Alessandro Giannessi v Vasek Pospisil | 6-3,3-6,6-4 | |
| Challenger Naples | 03/25 09:00 | 19 | Alessandro Giannessi v Evan Furness | Retired | |
| Challenger Naples | 03/24 10:45 | 14 | Alessandro Giannessi v Fabrizio K P Osti | 6-3,6-1 | |
| Challenger Zadar | 03/20 11:05 | 26 | [273] Timofey Skatov v Alessandro Giannessi [241] | 6-1,6-2 | |
| Challenger Zadar | 03/18 12:30 | 25 | [241] Alessandro Giannessi v Corentin Moutet [107] | 5-7,6-2,6-4 | |
| Challenger Székesfehérvár | 03/13 11:25 | 26 | [234] Alessandro Giannessi v Matteo Martineau [190] | 4-6,6-7 | |
| Challenger Székesfehérvár | 03/11 12:25 | 25 | [234] Alessandro Giannessi v Mathias Bourgue [272] | 6-4,1-6,6-4 | |
| Challenger Tenerife | 02/27 12:15 | 25 | [430] Carlos Lopez Montagud v Alessandro Giannessi [232] | Retired | |
| Challenger Tenerife | 02/20 10:00 | 25 | [183] Matteo Gigante v Alessandro Giannessi [234] | 6-2,6-3 | |
| Challenger Manama | 02/13 08:00 | 25 | [234] Alessandro Giannessi v Damir Dzumhur [160] | 3-6,1-6 | |
| ATP Córdoba | 02/03 15:50 | 14 | [135] Luciano Darderi v Alessandro Giannessi [223] | 6-2,6-0 | |
| Challenger Piracicaba | 01/30 17:00 | 25 | [263] Gianluca Mager v Alessandro Giannessi [223] | Retired | |
| Challenger Punta del Este | 01/23 16:00 | 25 | [138] Juan M Cerundolo v Alessandro Giannessi [226] | 1-6,6-4,6-1 | |
| Australian Open | 01/10 03:00 | 14 | [216] Alessandro Giannessi v John Millman [484] | 3-6,4-6 | |
| ATP Brisbane | 12/30 08:25 | 14 | [97] Alex Michelsen v Alessandro Giannessi [203] | 6-3,6-2 | |
| Challenger Maia | 11/28 10:30 | 25 | [206] Alessandro Giannessi v Henrique Rocha [255] | 4-6,7-6,2-6 | |
| Challenger Valencia | 11/22 11:45 | 26 | [212] Alessandro Giannessi v Albert Ramos-Vinolas [96] | 1-6,6-0,6-7 | |
| Challenger Valencia | 11/21 10:00 | 25 | [212] Alessandro Giannessi v Miguel Damas [417] | 6-2,6-4 | |
| Challenger Montevideo | 11/14 15:00 | 25 | [111] Facundo Diaz Acosta v Alessandro Giannessi [211] | 6-1,7-5 | |
| Challenger Lima | 11/08 18:30 | 26 | [217] Alessandro Giannessi v Daniel Elahi Galan [93] | 4-6,3-6 | |
| Challenger Lima | 11/07 17:45 | 25 | [217] Alessandro Giannessi v Oriol Roca Batalla [192] | 1-6,6-3,6-2 | |
| Challenger Olbia | 10/17 20:10 | 25 | [141] Lloyd Harris v Alessandro Giannessi [210] | 7-6,6-0 | |
| Challenger Lisabon | 10/02 14:10 | 25 | [139] Pablo Llamas Ruiz v Alessandro Giannessi [213] | 6-3,6-1 | |
| Challenger Braga | 09/27 12:55 | 26 | [199] Duje Ajdukovic v Alessandro Giannessi [213] | 7-5,5-7,6-2 | |
| Challenger Braga | 09/26 14:00 | 25 | [351] Gastao Elias v Alessandro Giannessi [215] | 6-7,4-6 | |
| Challenger Sibiu | 09/19 10:20 | 25 | Bor Artnak v Alessandro Giannessi | Retired | |
| Challenger Sevilla | 09/07 19:00 | 27 | [244] Alessandro Giannessi v Hugo Gaston [99] | 6-3,1-6,0-6 |
Alessandro Giannessi (* 30. května 1990 La Spezia) je italský profesionální tenista hrající levou rukou. Ve své dosavadní kariéře na okruhu ATP World Tour nevyhrál žádný turnaj. Na challengerech ATP a okruhu ITF získal do září 2016 šest titulů ve dvouhře a sedm ve čtyřhře.
Na žebříčku ATP byl ve dvouhře nejvýše klasifikován v dubnu 2012 na 126. místě a ve čtyřhře pak v říjnu 2013 na 171. místě. Trénují ho Gabrio Castrichella a Eduardo Infantino.
V italském daviscupovém týmu neodehrál žádné utkání.