2011–13: Assuming the captaincy

Messi scored his first international hat-trick against Switzerland in February 2012.
After Argentina's unsuccessful performance in the Copa América, Batista was replaced by Alejandro Sabella. Upon his appointment in August 2011, Sabella awarded the 24-year-old Messi the captaincy of the squad, in accord with then-captain Javier Mascherano. Reserved by nature, Messi went on to lead his squad by example as their best player, while Mascherano continued to fulfil the role of the team's on-field leader and motivator.[321][322] In a further redesign of the team, Sabella dismissed Tevez and brought in players with whom Messi had won the World Youth Championship and Olympic Games. Now playing in a free role in an improving team, Messi ended his goal drought by scoring during their first World Cup qualifying match against Chile on 7 October, his first official goal for Argentina in two-and-a-half years.[294][321]
Under Sabella, Messi's goalscoring rate drastically increased; where he had scored only 17 goals in 61 matches under his previous managers, he scored 25 times in 32 appearances during the following three years.[294][321] He netted a total of 12 goals in 9 games for Argentina in 2012, equalling the record held by Gabriel Batistuta for the most goals scored in a calendar year for their country.[323] His first hat-trick with the Albicelestes came in a friendly against Switzerland on 29 February 2012, followed by two more hat-tricks over the next year-and-a-half in friendlies against Brazil and Guatemala. Messi then helped the team secure their place in the 2014 World Cup with a 5–2 victory over Paraguay on 10 September 2013; in addition to providing an assist, he scored twice from a penalty kick, taking his international tally to 37 goals to become Argentina's second-highest goalscorer behind Batistuta. Overall, he had scored a total of 10 goals in 14 matches during the qualifying campaign.[294][324] Concurrently with his bettered performances, his relationship with his compatriots improved, as he gradually began to be perceived more favourably in Argentina.[321]
2014–15: World Cup and Copa América finals

Messi watches his 25-yard curling strike hit the net against Iran to win the game for Argentina in their second group game at the 2014 FIFA World Cup
Ahead of the World Cup in Brazil, doubts persisted over Messi's form, as he finished an unsuccessful and injury-plagued season with Barcelona. At the start of the tournament, however, he gave strong performances, being elected man of the match in their first four matches.[325] In his first World Cup match as captain, he led them to a 2–1 victory over Bosnia and Herzegovina; he helped create Sead Kolašinac's own goal and scored their second strike after a dribble past three players, his first World Cup goal since his debut in the tournament eight years earlier.[326] During the second match against Iran, he scored an injury-time goal from 25 yards out to end the game in a 1–0 win, securing their qualification for the knockout phase.[327] He scored twice in the last group match, a 3–2 victory over Nigeria, his second goal from a free kick, as they finished first in their group.[328] Messi assisted a late goal in extra time to ensure a 1–0 win against Switzerland in the round of 16, before starting the play that led to their match-winning 1–0 goal in the quarter-final against Belgium, helping Argentina progress to the semi-final of the World Cup for the first time since 1990.[329][330] Following a 0–0 draw in extra time, they eliminated the Netherlands 4–2 in a penalty shootout to reach the final, with Messi scoring his team's first penalty.[331]

Messi battles Germany's Mats Hummels for the ball during the final of the 2014 FIFA World Cup.
Billed as Messi versus Germany, the world's best player against the best team, the final was a repeat of the 1990 final featuring Diego Maradona.[332] Within the first half-hour, Messi had started the play that led to a goal, but it was ruled offside. He missed several opportunities to open the scoring throughout the match, in particular at the start of the second half when his breakaway effort went wide of the far post. Substitute Mario Götze finally scored in the 113th minute, followed in the last minute of extra time by a free kick that Messi sent over the net, as Germany won the match 1–0 to claim the World Cup.[333] At the conclusion of the final, Messi was awarded the Golden Ball as the best player of the tournament. In addition to being the joint third-highest goalscorer, with four goals and an assist, he created the most chances, completed the most dribbling runs, made the most deliveries into the penalty area and produced the most throughballs in the competition.[325][334] However, his selection drew criticism due to his lack of goals in the knockout round; FIFA President Sepp Blatter expressed his surprise, while Maradona suggested that Messi had undeservedly been chosen for marketing purposes.[335]
Another final appearance, the third of Messi's senior international career, followed in the 2015 Copa América, held in Chile. Under the stewardship of former Barcelona manager Gerardo Martino, Argentina entered the tournament as title contenders due to their second-place achievement at the World Cup.[336][337] During the opening match against Paraguay, they were ahead two goals by half-time but lost their lead to end the match in a 2–2 draw; Messi had scored from a penalty kick, netting his only goal in the tournament.[338] Following a 1–0 win against defending champions Uruguay, Messi earned his 100th cap for his country in the final group match, a 1–0 win over Jamaica, becoming only the fifth Argentine to achieve this milestone.[339] In his 100 appearances, he had scored a total of 46 goals for Argentina, 22 of which came in official competitive matches.[294][339]
As Messi evolved from the team's symbolic captain into a genuine leader, he led Argentina to the knockout stage as group winners.[340] In the quarter-final, they created numerous chances, including a rebound header by Messi, but were repeatedly denied by Colombia's goalkeeper, and ultimately ended the match scoreless, leading to a 5–4 penalty shootout in their favour, with Messi netting his team's first spot kick.[341] At the semi-final stage, Messi excelled as playmaker as he provided three assists and helped create three more goals in his side's 6–1 victory over Paraguay, receiving applause from the initially hostile crowd.[340] Argentina started the final as the odds-on title favourites, but were defeated by Chile 4–1 in a penalty shootout after an 0–0 extra-time draw. Faced with aggression from opposing players, including taking a boot to the midriff, Messi played below his standards, though he was the only Argentine to successfully convert his penalty.[342] At the close of the tournament, he was reportedly selected to receive the Most Valuable Player award but rejected the honour.[343] As Argentina continued a trophy drought that began in 1993, the World Cup and Copa América defeats again brought intense criticism for Messi from Argentine media and fans.[344]