| Challenger Oeiras | 05/15 09:00 | 19 | [230] Alessandro Giannessi v Daniel Michalski [289] | 6-4,6-4 | |
| Challenger Oeiras | 05/14 10:25 | 14 | [230] Alessandro Giannessi v Alberto Barroso Campos [452] | 6-1,6-3 | |
| Challenger Francavilla | 05/10 11:20 | 26 | [160] Benoit Paire v Alessandro Giannessi [230] | 7-5,7-5 | |
| Challenger Francavilla | 05/09 09:00 | 25 | [230] Alessandro Giannessi v Marco Trungelliti [227] | 3-6,6-3,6-4 | |
| Challenger Cagliari | 05/04 11:45 | 26 | [246] Alessandro Giannessi v Thanasi Kokkinakis [111] | 4-6,2-6 | |
| Challenger Cagliari | 05/03 10:25 | 25 | [246] Alessandro Giannessi v Francesco Passaro [120] | 3-6,7-6,6-4 | |
| Challenger Cagliari | 05/02 08:30 | 19 | [246] Alessandro Giannessi v Alexander Erler [36] | 7-5,6-1 | |
| Challenger Florianopolis | 04/21 16:15 | 27 | [253] Alessandro Giannessi v Benjamin Hassan [295] | 6-3,4-6,6-7 | |
| Challenger Florianopolis | 04/20 13:00 | 26 | [253] Alessandro Giannessi v Pedro B Dias [352] | 6-4,6-4 | |
| Challenger Florianopolis | 04/19 13:00 | 25 | [253] Alessandro Giannessi v Juan Bautista Otegui [402] | 6-2,6-3 | |
| Challenger Madrid | 04/09 12:30 | 14 | Alessandro Giannessi v David Jorda Sanchis | 6-3,6-7,3-6 | |
| ATP Estoril | 04/03 17:50 | 25 | [224] Alessandro Giannessi v Fabio Fognini [97] | 2-6,1-6 | |
| ATP Estoril | 04/02 11:00 | 19 | [128] Fabian Marozsan v Alessandro Giannessi [261] | 6-4,6-7,4-6 | |
| ATP Estoril | 04/01 12:15 | 14 | [261] Alessandro Giannessi v Oleksii Krutykh [167] | 1-6,7-5,6-1 | |
| Challenger Sanremo | 03/28 10:20 | 25 | [124] Giulio Zeppieri v Alessandro Giannessi [261] | 6-1,6-1 | |
| Challenger Zadar | 03/26 10:00 | 29 | [137] Sebastian Ofner v Alessandro Giannessi [261] | 4-6,7-5,6-7 | |
| Challenger Zadar | 03/25 12:00 | 28 | [261] Alessandro Giannessi v Arthur Cazaux [218] | 6-3,6-4 | |
| Challenger Zadar | 03/24 11:20 | 27 | [261] Alessandro Giannessi v Zsombor Piros [185] | 7-6,6-2 | |
| Challenger Zadar | 03/23 10:00 | 26 | [261] Alessandro Giannessi v Nino Serdarusic [249] | 7-6,6-3 | |
| Challenger Zadar | 03/21 14:10 | 25 | [221] Manuel Guinard v Alessandro Giannessi [261] | 4-6,2-6 | |
| Challenger Székesfehérvár | 03/16 09:00 | 26 | [235] Alessandro Giannessi v Flavio Cobolli [165] | 4-6,0-6 | |
| Challenger Székesfehérvár | 03/14 14:10 | 25 | [295] Nikolas S Izquierdo v Alessandro Giannessi [235] | 4-6,7-6,4-6 | |
| Challenger Antalya | 03/09 08:00 | 26 | [235] Alessandro Giannessi v Fabian Marozsan [163] | 6-7,2-6 | |
| Challenger Antalya | 03/07 07:00 | 25 | [235] Alessandro Giannessi v Lucas Gerch [316] | 7-6,6-1 | |
| Challenger Manama | 02/14 09:30 | 25 | [115] Tomas Machac v Alessandro Giannessi [233] | 6-2,2-6,6-2 | |
| Challenger Tenerife | 02/10 14:10 | 27 | [409] Stefano Travaglia v Alessandro Giannessi [255] | 6-3,6-4 | |
| Challenger Tenerife | 02/09 15:00 | 26 | [255] Alessandro Giannessi v Raul Brancaccio [124] | 6-3,6-2 | |
| Challenger Tenerife | 02/08 11:00 | 25 | [255] Alessandro Giannessi v Mikhail Kukushkin [217] | 6-4,0-6,6-3 | |
| Challenger Tenerife | 01/31 18:15 | 25 | [252] Alessandro Giannessi v Matteo Arnaldi [130] | 3-6,7-6,3-6 | |
| Challenger Piracicaba | 01/17 18:20 | 25 | [233] Alessandro Giannessi v Camilo Ugo Carabelli [127] | 4-6,6-3,1-6 |
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.