2018 Citi Open – Men's singles

Alexander Zverev was the defending champion and successfully defended his title, defeating Alex de Minaur in the final, 6–2, 6–4.

Seeds
All seeds receive byes into the second round. • 🇩🇪 Alexander Zverev (champion)

• 🇺🇸 John Isner (second round)

• 🇧🇪 David Goffin (quarterfinals)

• 🇬🇧 Kyle Edmund (second round)

• 🇦🇺 Nick Kyrgios (withdrew)

• 🇫🇷 Lucas Pouille (third round)

• 🇯🇵 Kei Nishikori (quarterfinals)

• 🇰🇷 Chung Hyeon (third round)

• 🇨🇦 Denis Shapovalov (third round)

• Stefanos Tsitsipas (semifinals)

• 🇺🇸 Steve Johnson (second round)

• 🇷🇺 Karen Khachanov (second round)

• 🇺🇸 Frances Tiafoe (third round)

• 🇫🇷 Jérémy Chardy (second round)

• 🇩🇪 Mischa Zverev (third round)

• 🇷🇺 Andrey Rublev (semifinals)

Seeds
The top four seeds receive byes into the qualifying competition. • # 🇦🇺 Jason Kubler (qualifying competition, lucky loser)

• # 🇮🇳 Ramkumar Ramanathan (qualifying competition)

• # Jason Jung (qualifying competition, retired)

• # 🇦🇺 Alex Bolt (qualified)

• # 🇺🇸 Christopher Eubanks (qualifying competition)

• # 🇨🇦 Filip Peliwo (first round)

• # 🇺🇸 Mitchell Krueger (qualified)

• # 🇺🇸 Donald Young (qualified)

• # 🇺🇸 Stefan Kozlov (first round)

• # 🇯🇵 Yosuke Watanuki (qualified)

• # 🇫🇷 Vincent Millot (qualified)

• # 🇺🇦 Illya Marchenko (first round)

Qualifiers
• # 🇯🇵 Yosuke Watanuki

• # 🇺🇸 Mitchell Krueger

• # 🇺🇸 Donald Young

• # 🇦🇺 Alex Bolt

• # 🇫🇷 Vincent Millot

• # 🇺🇸 Thai-Son Kwiatkowski

Lucky loser

 * 1) 🇦🇺 Jason Kubler