Match detailsFixture: Roberto Bautista Agut vs John IsnerDate: 30 March 2021Tournament: Miami Open 2021Round: Fourth Round (Round of 16)Venue: Miami, FloridaCategory: ATP Masters 1000 SeriesSurface: Outdoor hardcourtPrize money: $3,340,000Live telecast: USA - Tennis Channel | UK - EuropsortRoberto Bautista Agut vs John Isner previewSeventh seed Roberto Bautista Agut is set to face America's John Isner in the fourth round of the Miami Open on Tuesday.After getting a walkover in the first round, Bautista Agut had to endure a tough time against Jan-Lennard Struff in the second. The Spaniard lost the first set, but eventually made a comeback to win 4-6, 6-3, 6-2.Bautista Agut has had a rollercoaster season so far. He made the finals at Montpellier and Qatar, but was knocked out within the first two rounds at the Australian Open, the Dubai Championships and the Rotterdam Open.Miami 2019 SF: 7-6 7-6 💥Miami 2021 3R: 7-6 7-6 💥2018 @MiamiOpen champion @JohnIsner cuts and pastes his way to another victory over Felix Auger-Aliassime in Miami. pic.twitter.com/iU0qyA9hjQ— Tennis TV (@TennisTV) March 28, 2021John Isner on his part lost his first set of the tournament to compatriot Mackenzie McDonald, but came back strongly to win 2-6, 6-3, 7-5. He then took out youngster Felix-Auger Aliassime in straight sets, winning 7-6(5), 7-6(5).This is just Isner's third tournament of the year, after the Delray Beach Open and the Mexican Open. He was knocked out in his second match at both tournaments.Isner's performances in Miami have been exceptional in recent years. He won his first and only ATP 1000 title here in 2018, and made the final once again the following season.Roberto Bautista Agut vs John Isner head-to-headRoberto Bautista Agut and John Isner have met four times on tour so far, with the American leading the head-to-head 3-1. All four encounters between the duo have been on outdoor hardcourts, and all have been in the Round of 16 or later.Bautista Agut's only win over Isner came in the quarterfinal at Auckland in 2016, where he won 7-5, 2-6, 6-3.While all their fixtures up until that point were closely fought, Isner won their last meeting in straight sets. That match, incidentally, was at Miami, with the American winning 7-6(1), 7-6(5).Roberto Bautista Agut vs John Isner predictionJohn Isner has the chance to make three Miami finals in a rowWhile Roberto Bautista Agut is significantly higher-placed than John Isner in the current ATP rankings, he is by no means the outright favorite for this match. Isner has a solid record, both at this tournament and against Bautista Agut.While the Spaniard is blessed with solid baseline play and accurate groundstrokes, he will likely find it difficult to cope with Isner's splendid serve. The American has already slapped 31 aces in two matches at the tournament so far. Isner's power - both on the serve and off the ground - might prove too much for Bautista Agut to deal with on Tuesday.Prediction: John Isner to win in three sets.