1977 ATP Buenos Aires (April) – Singles
# 1977 ATP Buenos Aires (April) – Singles

Guillermo Vilas defeated Wojtek Fibak 6–4, 6–3, 6–0 to win the April 1977 ATP Buenos Aires singles competition. Vilas was the defending champion.

## Seeds

A champion seed is indicated in bold text while text in italics indicates the round in which that seed was eliminated.

* Guillermo Vilas (Champion)
* Wojciech Fibak (Final)

## Draw

### Key

* NB: All rounds up to but not including the final were the best of 3 sets. The final was the best of 5 sets.

### Final

| Final | Final | Final | Final | Final | Final | Final |
| - | - | - | - | - | - | - |
| 1 | Guillermo Vilas | 6 | 6 | 6 | | |
| 2 | Wojciech Fibak | 4 | 3 | 0 | | |

### Section 1

| First Round | First Round | First Round | First Round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| - | - | - | - | - | - | - | - | - | - | - | - |
| 1 | Guillermo Vilas | 6 | 6 | | | | | | | | |
| | Roberto Gratz | 1 | 3 | | | | | | | | |
| | Roberto Gratz | 1 | 3 | 1 | Guillermo Vilas | 6 | 6 | | | | |
| | | | | | Fernando Dalla Fontana | 2 | 4 | | | | |
| | Fernando Dalla Fontana | 6 | 6 | | Fernando Dalla Fontana | 2 | 4 | | | | |
| | Julián Ganzábal | 0 | 0 | | | | | | | | |
| | Julián Ganzábal | 0 | 0 | | | | | 1 | Guillermo Vilas | 6 | 6 |
| | | | | | | | | | Paolo Bertolucci | 3 | 2 |
| | Paolo Bertolucci | 6 | 7 | | | | | | | | | Paolo Bertolucci | 3 | 2 |
| | Jose Santiago | 4 | 5 | | | | | | | | |
| | Jose Santiago | 4 | 5 | | Paolo Bertolucci | 6 | 9 | | | | |
| | | | | | Ion Țiriac | 3 | 7 | | | | |
| | Ion Țiriac | 6 | 6 | | Ion Țiriac | 3 | 7 | | | | |
| | Lorenzo Soriano | 3 | 2 | | | | | | | | |

### Section 2

| First Round | First Round | First Round | First Round | Quarterfinals | Quarterfinals | Quarterfinals | Quarterfinals | Semifinals | Semifinals | Semifinals | Semifinals |
| - | - | - | - | - | - | - | - | - | - | - | - |
| Ricardo Cano | 3 | 6 | 6 | | | | | | | | |
| Lito Álvarez | 6 | 2 | 2 | | | | | | | | |
| Lito Álvarez | 6 | 2 | 2 | | Ricardo Cano | 6 | 6 | | | | |
| | | | | | Balázs Taróczy | 3 | 3 | | | | |
| Balázs Taróczy | 6 | 6 | | | Balázs Taróczy | 3 | 3 | | | | |
| Roberto Aubone | 4 | 2 | | | | | | | | | |
| Roberto Aubone | 4 | 2 | | | | | | | Ricardo Cano | 3 | 7 |
| | | | | | | | | 2 | Wojciech Fibak | 6 | 9 |
| Cliff Richey | 6 | 6 | | | | | | | | | | 2 | Wojciech Fibak | 6 | 9 |
| Carlos Landó | 1 | 2 | | | | | | | | | |
| Carlos Landó | 1 | 2 | | | Cliff Richey | 7 | 3 | | | | |
| | | | | 2 | Wojciech Fibak | 9 | 6 | | | | |
| Hector Romani | 3 | 3 | | 2 | Wojciech Fibak | 9 | 6 | | | | |
| Wojciech Fibak | 6 | 6 | | | | | | | | | |
