Zenit St. Petersburg bolstered its squad Monday, signing Brazilian striker Hulk and Belgian midfielder Axel Witsel to five-year deals and paying transfer fees reportedly worth a combined 80 million Euros ($100.7 million) to their Portuguese clubs- FC Porto and Benfica. It is being reported that Zenit paid 40 million Euros for each player.

Hulk and Witsel became Zenit's first major signings in the summer transfer window, which remains open in Russia for another week.

Having begun his career in Japanese football with Kawasaki Fontale, Consadole Sapporo and Tokyo Verdy, Hulk moved to the Os Dragoes in 2008 and helped the club to three league titles, three Tacas de Portugal and the UEFA Cup.

He has won 13 Brazil caps since making his debut in 2009, and was part of the Selecao's Olympic team that claimed silver in London. Hulk was linked with a move to Stamford Bridge this summer.

Witsel, a 23-year-old midfielder, only joined Benfica in 2011 from his hometown club Standard Liege, where he started his career in 2006. He was linked with a summer move to Real Madrid.

"We were trying to sign them before the Sept. 3 deadline for the Champions League so they can play for us in that competition as well as the Russian league," Zenit spokesman Dmitry Tsimmerman told Reuters.

Zenit was drawn last week in Group C of the Champions League along with AC Milan, Anderlecht and Malaga.

The 26-year-old Hulk will wear the No.29 shirt for Luciano Spalletti's side, who currently sit top of the Russian Premier League after seven games, while Witsel will take the No.28 jersey.

Zenit, backed by Russian energy giant Gazprom,will surely fancy themselves for success at both home and Europe with these two class acquisitions.

Portugal and Manchester United midfielder, Nani is also being linked with a move to Zenit, with reports coming in that Spalletti's are ready to make a 30 million pound offer for the player. Tsimmerman, however, declined to comment on Nani's possible transfer.