Nicolas Mahut and Pierre-Hugues Herbert survive a first-round test at the BNP Paribas Open.

John Peers and Henri Kontinen, the 2017 champions, congratulate Pierre-Hugues Herbert and Nicolas Mahut on Sunday after the Australian Open final.

Nicolas Mahut and Pierre-Hugues Herbert who completed the Career Grand Slam at the Australian Open, pose with Roy Emerson and Rod Laver.

Novak Djokovic, a few hours before playing Rafael Nadal in the singles final, congratulates Pierre-Hugues Herbert and Nicolas Mahut on completing the Career Grand Slam in Melbourne.

Nicolas Mahut and Pierre-Hugues Herbert celebrate becoming the eighth men's team in history to complete the Career Grand Slam with their first Australian Open crown.

Fifth seeds Nicolas Mahut and Pierre-Hugues Herbert beat 2017 champions Henri Kontinen and John Peers on Sunday in the Australian Open final.

Nicolas Mahut and Pierre-Hugues Herbert celebrate becoming the eighth team in history to capture the Career Grand Slam on Sunday at the Australian Open.

Nicolas Mahut and Pierre-Hugues Herbert make the semi-finals in Melbourne.

Pierre-Hugues Herbert and Nicolas Mahut defeat Ivan Dodig and Mate Pavic in four sets in the Davis Cup final on Saturday.

Pierre-Hugues Herbert watches on as Nicolas Mahut strikes a volley on Sunday in the doubles final at the Nitto ATP Finals.

Nicolas Mahut and Edouard Roger-Vasselin capture their sixth title as a team, triumphing at the European Open in Antwerp.

Nicolas Mahut and Edouard Roger-Vasselin triumph together at the Moselle Open for the second time by defeating Ken Skupski and Neal Skupski.

Frenchmen Julien Benneteau and Nicolas Mahut defeat Spain's Marcel Granollers and Feliciano Lopez to reach the 2018 Davis Cup final.

Nicolas Mahut and Pierre-Hugues Herbert, the 2015-16 champions, fall to Lleyton Hewitt and Nick Kyrgios on Wednesday at The Queen's Club.

Six-year-old Natanel Mahut ran onto Court Philippe-Chatrier to celebrate his father Nicolas Mahut's (right) first Roland Garros title.

Nicolas Mahut and Pierre-Hugues Herbert become the third all-French team in the Open Era to win the Roland Garros title.

Pierre-Hugues Herbert and Nicolas Mahut broke Oliver Marach and Mate Pavic (pictured) to lift their first Roland Garros title.

Pierre-Hugues Herbert and Nicolas Mahut defeat Oliver Marach (pictured) and Mate Pavic to claim their third Grand Slam trophy.

Nicolas Mahut and Pierre-Hugues Herbert clinch their first Roland Garros title, defeating Oliver Marach and Mate Pavic in straight sets.

Nicolas Mahut and Pierre-Hugues Herbert are bidding to win their first Roland Garros title on Saturday.

Frenchmen Nicolas Mahut and Pierre-Hugues Herbert defeat Nikola Mektic and Alexander Peya to secure their spot in the Roland Garros final.

Pierre-Hugues Herbert and Nicolas Mahut are bidding to become the third all-French team in the Open Era to win Roland-Garros.

Pierre-Hugues Herbert and Nicolas Mahut defeat Maximo Gonzalez and Nicolas Jarry to reach the semi-finals at Roland Garros on Wednesday.

Pierre-Hugues Herbert and Nicolas Mahut defeat Simone Bolelli and Fabio Fognini to earn France a 2-1 lead over Italy in the Davis Cup World Group quarter-finals on Saturday.

Nicolas Mahut and Pierre-Hugues Herbert close in on a routine victory over Damir Dzumhur and Filip Krajinovic on Sunday at the BNP Paribas Open.