New York Cosmos

Guenzatti moved back to the United States on July 5, 2013, when he signed for NASL club New York Cosmos.^[3] Guenzatti made his debut for the Cosmos on August 10, 2013, in a 0–0 draw against Tampa Bay.^[4] He scored the game-winning goal in the team's 1–0 win over Minnesota United FC on September 14, 2013, and earned NASL Team of the Week honors for his performance.^[5] The Uruguayan scored one goal and recorded one assist in ten matches for the Cosmos during the 2013 season and played 86 minutes during the team's 2013 NASL Soccer Bowl championship game 1–0 victory over the Atlanta Silverbacks.^[6]

On January 3, 2014, the Cosmos announced that they had signed Guenzatti to a contract extension.^[6]

During the 2014 Spring season, Guenzatti was tied for second on the team in scoring, recording two goals and two assists in seven matches as the team posted a 6–2–1 (W–L–D) record and finished in second place in the NASL Spring Standings.^[7] He earned NASL Team of the Week honors for his Week 7 goal in the team's 1–1 draw with Indy Eleven.^[8]

He finished the regular season tied for second on the team in scoring with four goals and three assists in 22 appearances (19 starts). He scored the game-winning goal in the team's 1–0 victory over Ottawa Fury FC on July 20, 2014, which earned him NASL Team of the Week honors and he combined with fellow Queens native David Diosa to score in the team's 3–2 win over the Atlanta Silverbacks on September 13, 2014.^[9][10]

In 2015, Guenzatti scored four times in 23 appearances, which included 10 starts. Guenzatti opened the scoring in back-to-back 3–0 wins over the Atlanta Silverbacks (October 7) and FC Edmonton (October 11). He racked up 986 minutes on the field in NASL play.

Tampa Bay Rowdies

On July 31, 2017, Guenzetti signed with United Soccer League side Tampa Bay Rowdies.^[11] Guenzatti was named team captain ahead of the 2019 season. On January 18, 2022, Guenzatti re-signed with the Rowdies.^[12]

On October 8, 2022, Guenzetti scored twice in a game against Loudoun United FC, passing his former teammate Georgi Hristov to become the Rowdies all-time scoring leader.^{[citation needed]}

On December 13, 2022, Tampa and Guenzetti mutually agreed to terminate his deal to allow him to pursue other opportunities.^[13] He subsequently signed with Indy Eleven on the same day.^[14]

Indy Eleven

Guenzatti signed with USL Championship side Indy Eleven ahead of the 2023 season and was subsequently named as the team's captain for the season.^[15] Guenzatti made his first appearance for the Eleven against his former Tampa Bay Rowdies in a 1–1 draw on March 11.^[16] Guenzatti scored his first goal for Indy Eleven in a 3–2 win against Monterey Bay FC on April 22, bringing his total career USL goal tally to 61.^[17]

Guenzatti scored a brace on August 9 in a 4–0 win over the Birmingham Legion, scoring on either side of halftime. The two goals brought his season total to 6.^[18]

Guenzatti ended the 2023 season with a team-leading 11 goals and 35 league and domestic appearances, as well as one playoff appearance and three total assists.^[19]

On November 17, 2023, Indy Eleven announced they had extended Guenzatti's contract for the 2024 season.^[20]

Guenzatti scored his first goal in the 2024 season on March 30, in a 2–1 defeat at home to Detroit City FC.^[21]