# 2018 Monterrey Challenger – Singles

Maximilian Marterer was the defending champion but chose not to defend his title.
David Ferrer won the title after defeating Ivo Karlović 6–3, 6–4 in the final.

## Seeds

* Marcel Granollers (quarterfinals)
* Michael Mmoh (withdrew)
* Paolo Lorenzi (first round)
* Adrián Menéndez Maceiras (first round)
* Ivo Karlović (final)
* David Ferrer (champion)
* Gerald Melzer (quarterfinals)
* Pedro Martínez (second round)

## Draw
### Key

* Q = Qualifier
* WC = Wild card
* LL = Lucky loser
* Alt = Alternate
* SE = Special exempt
* PR = Protected ranking
* ITF = ITF entry
* JE = Junior exempt
* w/o = Walkover
* r = Retired
* d = Defaulted
* SR = Special ranking

### Finals

| Semifinals | Semifinals | Semifinals | Semifinals | Semifinals | Final | Final | Final | Final |
| | Ernesto Escobedo | | | | | | | |
| 6 | David Ferrer | w/o | | | | | | |
| 6 | David Ferrer | w/o | | | 6 | David Ferrer | 6 | 6 |
| | | | | | 5 | Ivo Karlović | 3 | 4 |
| 5 | Ivo Karlović | 6$^6$ | 6 | 7$^7$ | 5 | Ivo Karlović | 3 | 4 |
| PR | Santiago Giraldo | 7$^8$ | 4 | 6$^3$ | | | | |

### Top half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals |
| 1 | M Granollers | 6 | 6 | | | | | | | | | | | | | |
| Q | Harrison Adams | 4 | 4 | | 1 | M Granollers | 6$^5$ | 7$^7$ | 7 | | | | | | | |
| | R Quiroz | 6$^8$ | 6 | 7 | | R Quiroz | 7$^7$ | 6$^3$ | 5 | | | | | | | |
| | M Arévalo | 7$^{10}$ | 3 | 5 | | | | | | 1 | M Granollers | 6$^5$ | 6$^4$ | | | |
| | M Valkusz | 0 | 3 | | | | | | | | E Escobedo | 7$^7$ | 7$^7$ | | | |
| | E Escobedo | 6 | 6 | | | E Escobedo | 5 | 6 | 6 | | | | | | | |
| | P Krstin | 6 | 6$^4$ | 3 | 8 | P Martínez | 7 | 4 | 3 | | | | | | | |
| 8 | P Martínez | 1 | 7$^7$ | 6 | | | | | | | | | | | E Escobedo | |
| 3 | P Lorenzi | 5 | 3 | | | | | | | | | | | 6 | D Ferrer | w/o |
| WC | J Melzer | 7 | 6 | | WC | J Melzer | 6 | 6$^4$ | 3 | | | | | | | |
| | S Ofner | 6 | 6 | | | S Ofner | 3 | 7$^7$ | 6 | | | | | | | |
| | M Vilella Martínez | 1 | 2 | | | | | | | | S Ofner | 3 | 4 | | | |
| | K King | 4 | 6 | 4 | | | | | | 6 | D Ferrer | 6 | 6 | | | |
| | R Cid Subervi | 6 | 2 | 6 | | R Cid Subervi | 2 | 7$^7$ | 2 | | | | | | | |
| | T Kokkinakis | 1 | 3 | | 6 | D Ferrer | 6 | 6$^4$ | 6 | | | | | | | |
| 6 | D Ferrer | 6 | 6 | | | | | | | | | | | | | |

### Bottom half

| First round | First round | First round | First round | First round | Second round | Second round | Second round | Second round | Second round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals | Semifinals |
| 5 | I Karlović | 7$^8$ | 7 | | | | | | | | | | | | | | | | |
| | T de Bakker | 6$^6$ | 5 | | 5 | I Karlović | 3 | 6 | 7$^7$ | | | | | | | | | | |
| | S Kozlov | 2 | 4 | | WC | L Gómez | 6 | 3 | 6$^4$ | | | | | | | | | | |
| WC | L Gómez | 6 | 6 | | | | | | | 5 | I Karlović | 6 | 6 | | | | | | |
| | B Fratangelo | 6 | 6 | | | | | | | | B Fratangelo | 4 | 3 | | | | | | |
| WC | G López Villaseñor | 3 | 2 | | | B Fratangelo | 6 | 6 | | | | | | | | | | | |
| Q | Z Piros | 6 | 5 | 7$^7$ | Q | Z Piros | 1 | 2 | | | | | | | | | | | |
| 4 | A Menéndez Maceiras | 1 | 7 | 6$^4$ | | | | | | | | | | | 5 | I Karlović | 6$^6$ | 6 | 7$^7$ |
| 7 | G Melzer | 7 | 6 | | | | | | | | | | | | PR | S Giraldo | 7$^8$ | 4 | 6$^3$ |
| | E King | 5 | 3 | | 7 | G Melzer | 7$^7$ | 4 | 6 | | | | | | | | | | |
| | N Serdarušić | 6 | 6 | | | N Serdarušić | 6$^4$ | 6 | 3 | | | | | | | | | | |
| WC | V Estrella Burgos | 3 | 1 | | | | | | | 7 | G Melzer | 7$^7$ | 5 | 3 | | | | | |
| Q | Pavel Krainik | 4 | 4 | | | | | | | PR | S Giraldo | 6$^5$ | 7 | 6 | | | | | |
| PR | S Giraldo | 6 | 6 | | PR | S Giraldo | 4 | 6 | 6 | | | | | | | | | | |
| Q | G Escobar | 6 | 6 | | Q | G Escobar | 6 | 2 | 4 | | | | | | | | | | |
| LL | S Bangoura | 4 | 3 | | | | | | | | | | | | | | | | |