| French Open | 05/19 08:00 | 19 | [173] Alessandro Giannessi v Sebastian Ofner [218] | 4-6,6-1,2-6 | |
| French Open | 05/18 08:00 | 15 | [173] Alessandro Giannessi v Thiago Agustin Tirante [192] | 7-5,6-2 | |
| French Open | 05/16 11:30 | 14 | [117] Mats Moraing v Alessandro Giannessi [173] | 6-7,0-6 | |
| Challenger Bordeaux | 05/08 10:05 | 14 | [169] Alessandro Giannessi v Matteo Martineau [392] | 2-6,6-4,4-6 | |
| Challenger Řím | 04/26 13:15 | 25 | [160] Alessandro Giannessi v Denis Yevseyev [345] | Retired | |
| Challenger Madrid | 04/12 14:30 | 25 | [164] Alessandro Giannessi v Marco Trungelliti [194] | 2-6,6-2,3-6 | |
| Challenger Oeiras | 04/10 12:25 | 29 | [178] Alessandro Giannessi v Gastao Elias [173] | 6-7,1-6 | |
| Challenger Oeiras | 04/09 09:00 | 28 | [181] Jozef Kovalík v Alessandro Giannessi [178] | 6-2,4-6,5-7 | |
| Challenger Oeiras | 04/08 11:20 | 27 | [153] Christopher O'Connell v Alessandro Giannessi [178] | 4-6,4-6 | |
| Challenger Oeiras | 04/07 11:10 | 26 | [337] Fabian Marozsan v Alessandro Giannessi [178] | 7-5,6-7,4-6 | |
| Challenger Oeiras | 04/05 15:50 | 25 | [298] Luciano Darderi v Alessandro Giannessi [178] | 6-4,6-7,1-6 | |
| Challenger Oeiras | 04/02 09:00 | 28 | [174] Alessandro Giannessi v Gastao Elias [198] | 3-6,3-6 | |
| Challenger Oeiras | 04/01 10:30 | 27 | [174] Alessandro Giannessi v Giulio Zeppieri [239] | 1-6,7-5,6-3 | |
| Challenger Oeiras | 03/30 11:20 | 26 | [174] Alessandro Giannessi v Riccardo Bonadio [256] | 6-2,6-1 | |
| Challenger Oeiras | 03/28 16:10 | 25 | [174] Alessandro Giannessi v Nicola Kuhn [246] | 6-3,6-4 | |
| Challenger Roseto | 03/19 10:00 | 28 | [199] Manuel Guinard v Alessandro Giannessi [186] | 7-5,6-1 | |
| Challenger Roseto | 03/18 12:15 | 27 | [240] Zsombor Piros v Alessandro Giannessi [186] | 2-6,5-7 | |
| Challenger Roseto | 03/17 10:00 | 26 | [186] Alessandro Giannessi v Andrea Pellegrino [201] | 6-4,6-2 | |
| Challenger Roseto | 03/15 12:45 | 25 | [186] Alessandro Giannessi v Nicolas Alvarez Varona [304] | 3-6,6-1,6-3 | |
| Challenger Roseto | 03/10 10:00 | 26 | [288] Lukáš Rosol v Alessandro Giannessi [186] | 6-3,6-4 | |
| Challenger Roseto | 03/08 12:15 | 25 | [186] Alessandro Giannessi v Andrej Martin [127] | 6-0,2-6,6-4 | |
| Challenger Gran Canaria | 02/28 16:40 | 25 | [184] Alessandro Giannessi v Lukáš Rosol [297] | 6-7,6-3,6-7 | |
| ATP Santiago | 02/19 15:00 | 14 | [224] Felipe Meligeni Rodrigues Alves v Alessandro Giannessi [197] | 6-2,6-4 | |
| ATP Buenos Aires | 02/05 16:00 | 14 | [109] Hugo Dellien v Alessandro Giannessi [184] | 7-6,6-1 | |
| ATP Córdoba | 01/29 15:00 | 25 | [129] Juan Pablo Varillas v Alessandro Giannessi [184] | 7-6,6-2 | |
| Australian Open | 01/14 05:30 | 19 | [126] Yannick Hanfmann v Alessandro Giannessi [184] | 7-6,7-6 | |
| Australian Open | 01/12 05:10 | 15 | [184] Alessandro Giannessi v Quentin Halys [153] | 3-6,6-3,7-6 | |
| Australian Open | 01/11 02:30 | 14 | [183] Marc-Andrea Huesler v Alessandro Giannessi [184] | 4-6,6-3,3-6 | |
| Challenger Pau | 11/16 14:50 | 25 | [188] Alessandro Giannessi v Georgii Kravchenko [397] | 5-7,6-4,2-6 | |
| Challenger Ortisei | 11/09 10:25 | 25 | [191] Alessandro Giannessi v Nerman Fatic [317] | 7-6,3-6,5-7 |
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.