Skoda Xanthi Petros Mantalos began playing professional football for
Super League club
Skoda Xanthi. He played a total of 90 games (15 goals, 10 assists) in all competitions and represented his country at
under-19 and
under-21 levels. His performances attracted the interest of Greek giants
Olympiacos,
Panathinaikos and
AEK Athens, the latter club newly relegated from the Super League, bankrupt, and making a fresh start in the third-tier
Football League 2. In July 2013, Mantalos agreed to join AEK from the 2014–15 season. The fee was reported as around €500,000. He remained with Xanthi for the 2013–14 season, making 30 Super League appearances as well as playing in the
UEFA Europa League.
AEK Athens By the time Mantalos joined up with AEK, they had been promoted to the second-tier
Football League. He made his debut on 12 September in the first round of the
Greek Cup, and his first league appearance on 19 October 2014 at home to
Apollon Smyrnis: with his team losing 1–0, Mantalos took the free kick from which
Alexandre D'Acol equalised and then converted a
penalty to complete a 2–1 win. He went on to score 11 goals and provide 15 assists in 22 games in League and Cup combined. Mantalos himself missed the last few weeks of the season, having ruptured his
anterior cruciate ligament while playing in a cup derby against Olympiacos in March 2015. He said afterwards that it was his first major injury, he was not going to rush his recovery, and that AEK could manage well enough without him. This they proved, finishing
top of the South Group and then winning
the play-offs. After six months out, Mantalos returned to competitive action and continued as a regular in the first team, helping AEK finish third in the
2015–16 season and qualify for the Europa League. He scored the only goal of the first leg of the
Greek Cup semi-final against
Atromitos, and captained the side in
the final at the
Olympic Stadium. His first-half headed goal contributed to AEK's 2–1 defeat of champions Olympiacos to win the competition for the 15th time, and he was named MVP of the match. According to an end-of-season profile, Mantalos "endured a difficult start to
the campaign", "but seemed rejuvenated once
Manolo Jiménez took over the team" in January 2017. He finished the season with a goal and an assist in a 2–1 win against
Panionios in the
play-offs that confirmed AEK's place in the
UEFA Champions League third qualifying round, and was voted best Greek footballer in the Super League at the
PSAP awards. In light of interest from Spanish clubs, AEK were reported to be unwilling to sell at less than €5 or € million, as the player still had two years left on his contract. AEK went top of the Super League three weeks into the
2017–18 season after a 4–0 win over
AEL, in which Mantalos opened the scoring with a fourth-minute
bicycle kick. Although AEK failed to progress in the Champions League, they qualified for the
Europa League group stage; in their first match, Mantalos scored as AEK beat
Rijeka 2–1. A few days later, he scored an 89th-minute winner as they came back from 2–0 down after 63 minutes to beat reigning champions Olympiacos 3–2. At the end of October, Mantalos suffered another ruptured ACL, this time in his left knee. As a gesture of support, the club offered Mantalos a contract extension until 2022, which he accepted. He returned to action as a substitute on 21 April as AEK beat
Levadiakos to clinch their first Super League title since 1994. Mantalos converted a penalty in a 1–1 draw in the
Champions League play-off round second leg against
Vidi that, despite having two men sent off, was enough to progress to the
group stage on aggregate. Two days after reports emerged that the club had rejected a bid valued at €10 million for Mantalos from English
Championship club
West Bromwich Albion, he scored his first goal of the
2018–19 Super League season, a penalty, that gave AEK a 1–0 win away to
Asteras Tripolis. His fourth league goal, which opened the scoring in a 2–0 win away to Panionios in January 2019, was controversial as he appeared to handle the ball when controlling the final pass. Mantalos scored twice against Atromitos in the quarter-final of
that season's Greek Cup as AEK went on to reach and lose to
PAOK in the final for the third year running. Mantalos scored in both legs of AEK's
2019–20 Europa League qualifier against
Universitatea Craiova, but despite his goal in the
play-off round against
Trabzonspor, the tie ended 3–3 on aggregate and AEK were eliminated on
away goals. On 20 October 2019, he scored a brace sealing a vital 3–2 home win game against
Volos. It was elected MVP of the game. On 7 December 2019, he scored with an excellent kick in a hammering 5–0 home win game against
Panionios. On 18 December 2019, Mantalos opened the scoring from the penalty spot after six minutes to put
Massimo Carrera’s AEK in front in a 2–1 home win game against
Asteras Tripolis. On 23 February 2020, Mantalos scored with a diagonal header into the corner, after five minutes from a
Marko Livaja's cross, in a 3–0 home win game against
OFI. On 4 March 2020,
Marko Livaja picked out the onrushing Mantalos on the left, and the latter calmly stroked the ball into the far corner beyond
Julián Cuesta, opening the score in a slender 2–1 advantage against
Aris in Athens, with the second leg of the
Greek Cup semi-final to be played at the
Kleanthis Vikelidis Stadium next month. At the end of the regular season, Mantalos has showed a consistency throughout the entire campaign and as a result clubs from Turkey, including Super Lig leaders
İstanbul Başakşehir, are reportedly eager to sign the 28-year-old in the upcoming transfer window. At mid August 2020, UAE Pro League club
Al-Nasr offer an amount of €4.3 million for the Greek international. According to information, AEK are considering the proposal from Al-Nasr, with negotiations continuing between the two organisations. Mantalos would reportedly earn in the region of €1 million per year with Al-Nasr, but the transfer is not completed. On 19 September 2020, in the
2020–21 Super League Greece opener, Mantalos scored as a substitute sealing a 2–0 away win against
Panetolikos. On 5 November 2020, he scored in a 4–1 away win
2020–21 UEFA Europa League group stage game against
Zorya Luhansk helping AEK to increase the possibility of qualifying for the next phase of the
UEFA Europa League. On 22 November 2020, Mantalos made an impressive performance, giving 3 assists and receiving the Man of the Match award in a 4–1 home win against
AEL. On 19 March 2021, Mantalos renew his contract with the club until the summer of 2024. On 9 May 2021, he scored a vital goal sealing a 1–0 away victory against rivals
Panathinaikos in his club effort to gain the last ticket for
2021–22 UEFA Europa Conference League. On 30 July 2021, Mantalos scored with a penalty kick at the last moment of the
UEFA Europa Conference League game, but AEK faced a frustrated defeat with 3–2 on penalties against
FK Velež Mostar, with
Sergio Araujo losing the decisive penalty for the club. In the three last seasons, starting from
2019–20 season he has more than 10 assists per year. ==International career==