| Norman ITF | Round | Result | H | A | 
		
			| 14.11. |  | Pierson R. - Guillermo L. | Q-R16 | 6-2, 6-4 | 2.43 | 1.49 | 
		
			| 13.11. |  | Guillermo L. - Rioux L. | Q-2R | 6-2, 6-1 |  |  | 
		
			| 12.11. |  | Guillermo L. - Iyengar S. | Q-1R | 6-2, 6-0 |  |  | 
		
			| Toronto ITF | Round | Result | H | A | 
		
			| 30.10. |  | Bovina E. - Guillermo L. | Q-QF | 6-4, 6-2 | 1.43 | 2.60 | 
		
			| 29.10. |  | Guillermo L. - Parks A. | Q-R16 | 6-2, 7-5 | 1.29 | 3.35 | 
		
			| 28.10. |  | Guillermo L. - Zecevic S. | Q-1R | 6-0, 6-1 | 1.06 | 8.00 | 
		
			| Macon 2 ITF | Round | Result | H | A | 
		
			| 24.10. |  | Li A. - Guillermo L. | Q-QF | 7-62, 4-6, 6-0 | 1.39 | 2.78 | 
		
			| 23.10. |  | Guillermo L. - Chang H. | Q-R16 | 6-1, 6-4 | 2.89 | 1.36 | 
		
			| 22.10. |  | Guillermo L. - Paigina M. | Q-1R | 6-3, 3-6, 7-5 | 3.36 | 1.29 | 
		
			| Templeton ITF | Round | Result | H | A | 
		
			| 26.09. |  | Santamaria S. - Guillermo L. | Q-QF | 6-1, 1-6, 6-2 | 1.37 | 2.79 | 
		
			| 25.09. |  | Guillermo L. - Guarachi A. | Q-R16 | 7-5, 7-63 | 2.13 | 1.62 | 
		
			| 24.09. |  | Guillermo L. - Schenck S. | Q-1R | 6-0, 6-1 | 1.00 | 17.00 | 
		
			| Redding ITF | Round | Result | H | A | 
		
			| 14.09. |  | Whoriskey C. - Guillermo L. | R16 | 6-2, 7-64 | 1.56 | 2.22 | 
		
			| 13.09. |  | Guillermo L. - Sanchez M. | 1R | 2-6, 6-4, 6-2 | 6.53 | 1.06 | 
		
			| Fort Worth ITF | Round | Result | H | A | 
		
			| 03.08. |  | Minokoshi M. - Guillermo L. | R16 | 6-2, 6-2 | 1.77 | 1.92 | 
		
			| 03.08. |  | Guillermo L. - Perez E. | 1R | 7-5, 6-2 | 4.03 | 1.20 | 
		
			| Evansville ITF | Round | Result | H | A | 
		
			| 29.07. |  | Li A. - Guillermo L. | SF | 6-2, 3-6, 6-3 | 1.16 | 4.36 | 
		
			| 28.07. |  | Guillermo L. - Whoriskey C. | QF | 6-3, 6-0 | 4.95 | 1.12 | 
		
			| 27.07. |  | Guillermo L. - Morozova A. | R16 | 4-6, 6-1, 6-2 | 2.67 | 1.40 | 
		
			| 26.07. |  | Guillermo L. - Yarlagadda A. | 1R | 6-3, 7-65 | 1.71 | 1.98 | 
		
			| 25.07. |  | Guillermo L. - Fodor C. | Q-R16 | 6-3, 4-6, 6-1 |  |  | 
		
			| 24.07. |  | Guillermo L. - Blakely A. | Q-2R | 6-4, 6-2 |  |  | 
		
			| 23.07. |  | Guillermo L. - Vidic Z. | Q-1R | 6-0, 6-1 |  |  | 
		
			| Stockton ITF | Round | Result | H | A | 
		
			| 16.07. |  | Gordon M. - Guillermo L. | Q-1R | 6-2, 6-4 | 1.14 | 4.85 | 
		
			| Winnipeg ITF | Round | Result | H | A | 
		
			| 08.07. |  | Kuhlman J. - Guillermo L. | Q-1R | 63-7, 6-4, 6-1 |  |  | 
		
			| Victoria 3 ITF | Round | Result | H | A | 
		
			| 21.06. |  | Kinard T. - Guillermo L. | R16 | 6-4, 6-2 | 1.17 | 4.28 | 
		
			| 19.06. |  | Guillermo L. - Luk S. | 1R | 6-1, 6-1 | 1.02 | 9.60 | 
		
			| 18.06. |  | Guillermo L. - Zhang A. | Q-R16 | 6-3, 6-0 | 1.08 | 7.00 | 
		
			| 17.06. |  | Guillermo L. - Mansouri Y. | Q-1R | 6-1, 6-2 |  |  | 
		
			| Indian Wells - pre-qualifier | Round | Result | H | A | 
		
			| 01.03. |  | Karatantcheva S. - Guillermo L. | 2R | 6-4, 6-4 |  |  | 
		
			| 28.02. |  | Guillermo L. - Roth A. | 1R | 6-0, 6-2 |  |  | 
		
			| Rancho Santa Fe ITF | Round | Result | H | A | 
		
			| 21.02. |  | Sanchez M. - Guillermo L. | Q-R16 | 6-2, 6-2 | 1.07 | 6.51 | 
		
			| 20.02. |  | Guillermo L. - Wacnik J. | Q-2R | 6-1, 2-0 |  |  | 
		
			| 19.02. |  | Guillermo L. - Knickerbocker N. | Q-1R | 6-2, 6-0 |  |  | 
		
			| Surprise ITF | Round | Result | H | A | 
		
			| 14.02. |  | Dolehide C. - Guillermo L. | Q-R16 | 6-1, 6-3 | 1.05 | 7.12 | 
		
			| 13.02. |  | Guillermo L. - Ivanova D. | Q-2R | 66-7, 6-4, 6-1 |  |  | 
		
			| 12.02. |  | Guillermo L. - Wei Z. | Q-1R | 6-2, 7-69 |  |  |