He spent a season with La Liga club Levante, he played for Seattle Sounders FC of Major League Soccer from 2013 to 2015, scoring 40 goals, before spending several years in China with Shanghai Shenhua and Wuhan.

His first season in Italy saw Martins break into the first team squad, and later in the year Serie A sides Perugia and Inter Milan made offers for the forward.

[6] His form for the youth side led to his first-team league debut the following season, starting in a match against Parma on 22 December 2002 which was won by Inter 2–1.

During this season he was given his first UEFA Champions League appearance by manager Héctor Cúper, entering as a substitute against his future employers, Newcastle United, at St James' Park.

He scored his first Champions League goal in a match against Bayer 04 Leverkusen to secure Inter's place in the quarter-finals; footage of his celebratory somersaults were subsequently used by UEFA to advertise the following season's competition.

[10] He was also protagonist in team's successful run in Coppa Italia, scoring six goals, including a hat-trick against Bologna,[11] as the tournament ended in conquest.

[12] Martins amassed 22 goals in 45 matches across all competitions, setting a new personal best; his good form for Inter earned him a spot in Nigeria's 2006 Africa Cup of Nations squad.

[14] After Martins submitted a transfer request,[14] Premier League club Newcastle United completed a deal with Inter for the striker on 24 August 2006 for €15 million.

He was paraded in front of the Geordie fans before their UEFA cup tie against FK Ventspils, and inherited the club's cherished number 9 shirt, vacated after the retirement of the club-record goalscorer Alan Shearer in April.

This strike was clocked by Sky Sports at a speed of 84 mph (135 km/h), making it unofficially the ninth hardest shot ever recorded in football according to the Guardian website.

With new manager Sam Allardyce preferring to play Michael Owen and Mark Viduka up front, Martins found himself being used as an impact substitute for the first half of the season.

Despite this he managed to score consistently, and when Allardyce was sacked and Kevin Keegan was appointed, Martins found himself being used as part of a three pronged attack along with Owen and Viduka.

[21] He initially reiterated his desire to stay and help the club return to the Premier League for the 2009–10 season, but he eventually left for VfL Wolfsburg.

He signed a three-year contract and told BBC Sport: "I am joining a team of champions and I hope to bring my best to the club to make them even greater."

Martins' agent, Nicola Walter, revealed that Rubin met all of the player's requirements and that manager Kurban Berdyev had a "massive role" for him to play, following the departure of striker Aleksandr Bukharov.

[25] On 31 January 2011, he joined Premier League club Birmingham City on loan until the end of the season,[26] with the option of a £5 million permanent deal in the summer of 2011.

[27] He made his debut, which had been delayed by the formalities of obtaining a working visa, in the starting eleven against Stoke City on 12 February; he played for 75 minutes as Birmingham won 1–0.

[30] Martins scored the winning goal in the 2011 Football League Cup Final as Birmingham beat Arsenal 2–1 at Wembley Stadium, having been brought on as an 83rd-minute substitute.

With one minute remaining in normal time, there was a moment of confusion between Arsenal goalkeeper Wojciech Szczęsny and defender Laurent Koscielny as they attempted to deal with a headed knock down from Birmingham's Nikola Žigić.

[32] After two more Premier League appearances, he spent several weeks out with an injury eventually diagnosed as a stress fracture of the left tibia.

[36] Martins scored a brace for Levante in their 3–1 home victory over Granada on 28 October, sending his side into fourth place in the La Liga standings.

[41] The following day, Martins provided an assist for Marco Pappa's first goal as Seattle defeated the Galaxy 2–0 to win the Supporters' Shield.

[50] However, he suffered a partial rupture of tendon of quadriceps femoris at his right knee in the fifth group stage match of 2018 AFC Champions League against Kashima Antlers on 3 April 2018, which ruled him out for at least six months.

[54] On 20 September 2020, after his Shanghai Shenhua contract was terminated, Martins joined Chinese Super League club Wuhan Zall on a short-term deal until the end of the season.

[65] A fast, diminutive, and agile left-footed striker, who is quick on the ball, Martins is primarily known for his outstanding pace, mobility, and athleticism as a footballer, as well as his striking power, strength, and his elevation, despite his small stature; he has also stood out for his acrobatic goal celebrations.

[74] Inter Milan[78] Newcastle United Birmingham City[92] Rubin Kazan[78] Seattle Sounders FC[78] Shanghai Shenhua[49] Nigeria Individual