The fourth-seeded Djokovic suffered a second consecutive opening defeat, after losing his opener against Alejandro Tabilo in Monte Carlo two weeks ago.
Djokovic, who is eyeing his 100th tour-level title before the French Open starts on May 25, said no player would ever be bigger than tennis.
World number three Carlos Alcaraz withdrew from the Madrid Open on Thursday with a thigh injury, in a blow for his French Open title defence preparations.
Iga Swiatek admits the strict doping protocols can be stressful for players but feels like she has "been through the worst" after surviving her positive test over contaminated melatonin.
The 38-year-old Spaniard, winner of 22 Grand Slam trophies, including 14 at Roland Garros, retired from the sport after his final match at the Davis Cup in Malaga in November.
Holger Rune beat world number two Carlos Alcaraz 7-6 (8/6), 6-2 on Sunday to win the Barcelona Open for the first time.
The top-seeded Zverev, appearing in his first final since losing to Jannik Sinner in the Australian Open title decider in January, had little trouble dealing with Shelton, ranked 15 in the world.
Carlos Alcaraz battled into the semi-finals of the Barcelona Open on Friday with a 7-5, 6-3 win over Alex de Minaur after Casper Ruud's title defence was ended by Holger Rune.
The fourth-seeded Djokovic suffered a second consecutive opening defeat, after losing his opener against Alejandro Tabilo in Monte Carlo two weeks ago.
Djokovic, who is eyeing his 100th tour-level title before the French Open starts on May 25, said no player would ever be bigger than tennis.
World number three Carlos Alcaraz withdrew from the Madrid Open on Thursday with a thigh injury, in a blow for his French Open title defence preparations.
Iga Swiatek admits the strict doping protocols can be stressful for players but feels like she has "been through the worst" after surviving her positive test over contaminated melatonin.
The 38-year-old Spaniard, winner of 22 Grand Slam trophies, including 14 at Roland Garros, retired from the sport after his final match at the Davis Cup in Malaga in November.
Holger Rune beat world number two Carlos Alcaraz 7-6 (8/6), 6-2 on Sunday to win the Barcelona Open for the first time.
The top-seeded Zverev, appearing in his first final since losing to Jannik Sinner in the Australian Open title decider in January, had little trouble dealing with Shelton, ranked 15 in the world.
Carlos Alcaraz battled into the semi-finals of the Barcelona Open on Friday with a 7-5, 6-3 win over Alex de Minaur after Casper Ruud's title defence was ended by Holger Rune.
Sinner accepted a three-month ban in February following an agreement with the World Anti-Doping Agency, which challenged an independent tribunal's decision to clear him of wrongdoing after two positive tests for the anabolic agent clostebol.
World number two Carlos Alcaraz came back from a break down in the second set to defeat Ethan Quinn 6-2, 7-6 (8/6) and reach the Barcelona Open last 16 on Tuesday.
