Jupp Heynckes told Arturo Vidal to shape up in order to get back to top form for Bayern Munich.
Influential midfielder Vidal opened the scoring and starred in a 3-0 win at Augsburg on Saturday.
Bayern sit six points clear of Schalke at the top of the Bundesliga, with Borussia Dortmund's faltering form lending an additional boost to their hopes of winning a sixth consecutive top-flight crown.
Things were not so rosy earlier in the season as Carlo Ancelotti was sacked in the wake of a Champions League thrashing at Paris Saint-Germain and Vidal was one of a number of key players short of their best.
Chile's Confederations Cup final defeat to Germany and subsequent failure to qualify for the 2018 World Cup appeared to have left the 30-year-old in something of a malaise.
Having taken the reins from the deposed Ancelotti, Heynckes told Vidal the route out of his predicament was some good old-fashioned hard work.
Vamos por esos 3 puntos equipo!!!!!MiaSanMia!!pic.twitter.com/fFW5iaFcNQ— Arturo Vidal (@kingarturo23) November 18, 2017
"I had a conversation with him two-and-a-half weeks ago," the 72-year-old said, as quoted by Bild.
"I told him that I was not so happy with his physical condition and that he needs to make a difference if he wants to play.
"He did not quite see it that way but, from that point on, he trained differently."
Bayern travel to Anderlecht in the Champions League on Wednesday with a place in the last 16 already secure.
21. August 2018
|Ronaldo shares snap of ´Juventus family´|
|Aguero is the Premier League´s best foreign import, says Shearer|
|Real Madrid warned they must pay Rodrigo´s €120m release clause|
|England´s Broad fined for Pant rant|
|India on brink of victory after brilliant Bumrah halts Buttler|
|Serena Williams elevated to 17th seed at US Open|
|Kombouare signs new two-year Guingamp contract|
|Scaloni unclear on Messi´s long-term Argentina plans|
|F1 Raceweek: Gasly and Alonso restore focus at Spa|
|Nouri able to communicate, brother reveals|
|Pjanic extends Juventus contract to 2023|
|Odegaard joins Vitesse in latest loan from Real Madrid|
|Luck ´sort of happy´ with sack from Suggs|
|Manchester United´s Sanchez will ´be back soon´|
|Former Giants star Cruz announces retirement|
|RFU set Cipriani disciplinary date despite RPA complaints|
|Spalletti fined €10,000 for ´gravely offensive´ referee comments|
|IndyCar driver Wickens has spinal surgery after Pocono crash|
|Tiger: No doubt this is one of my best years|
|Vice-captain Tiger trying to remain objective in Ryder Cup conversations|
|Ronaldo won´t win Serie A by himself, warns Allan|
|Moeen sends message to England selectors with double century|
|Brunt calls time on Northern Ireland career|
|Tottenham´s Janssen sidelined after foot surgery|
|Liu Xiang breaks women´s 50m backstroke world record at Asian Games|
|Atletico Madrid winger Vitolo suffers knee ligament damage|
|Leverkusen teen Havertz aiming to emulate idol Ozil|
|Beckham to be honoured with UEFA President´s Award|
|CPS drops Hillsborough charges against Bettison|
|Who can take over from Federer, Nadal & Djokovic? Agassi backs Zverev, Kyrgios|
|´Freak incident´ rules Dragons´ Vaughan out for season|
|Kompany: Different Manchester City must not be complacent|
|Toyota withdraw appeal over Alonso´s Silverstone disqualification|
|Manchester City offload defender Denayer to Lyon|
|RPA want RFU to drop Cipriani charge|
|Cheika still the right man for Australia - Polota-Nau|
|Bolt not giving up on Manchester United dream|
|All Blacks must improve ´average´ set-piece, says Smith|
|Raiola hits back at Scholes following Pogba criticism|
|Indians top Red Sox in series opener|
|Struff stuns Cecchinato, Jarry reaches last 16|
|I´ll prove people wrong - Bolt completes first Mariners training session|
|Former champ Kvitova tops Radwanska, Pliskova ousted|
|Sad if it´s Filipe Luis´ last game for Atletico - Oblak|
|White Sox manager Rick Renteria hospitalised before game|
|Carragher: Van Dijk can become Liverpool legend|
|No timetable for Sale return from shoulder injury|
|This is a partnership - Rodgers on contract negotiations with Packers|
|Eagles QB Wentz unsure he´ll be cleared to play opener|
|Balotelli staying at Nice|
|It wasn´t a penalty, says Hodgson as Palace boss fumes at refereeing decisions|
|Salah can play much better - Klopp demands more from Liverpool star|
|Gasly to Red Bull: Vettel, Verstappen and the drivers who took their Toro Rosso chance|
|Klopp in the dark on Karius future amid links to Besiktas|
|Simeone pleased with draw after rigours of Super Cup|
20. August 2018
|Captain Reus saves Dortmund in DFB-Pokal|
|I couldn´t care less - Klopp rejects title challenge talk|
|Ailing Bairstow keen to aid England´s unlikely victory bid at Trent Bridge|
|Redskins secure Peterson signing|
|Manchester City goalkeeper Bravo suffers ruptured Achilles|
|Crystal Palace 0 Liverpool 2: Milner and Mane secure victory at Selhurst Park|
|Whyte takes aim at ´coward´ Fury ahead of Wilder showdown|
|Jets delighted with Darnold, open to trading Bridgewater|
|Gasly to replace Ricciardo at Red Bull|
|Valencia 1 Atletico Madrid 1: Rodrigo strikes to deny Simeone´s side|
|Injured Halep withdraws from Connecticut Open|
|Cipriani fined £2,000 by Gloucester|
|Mourinho will be sacked before Christmas, says Sharpe|
|England face record chase after Kohli smashes India to huge lead|
|Ozil captaining Arsenal a miracle - Hoeness|