By Iain Rogers

MADRID, Oct 2 (Reuters) - Atletico Madrid's impressive 2-1 comeback win at Porto in Champions League Group G on Tuesday was another sign the in-form La Liga side may have what it takes to mount a genuine challenge for the European title this season.

Buoyed by a stunning 1-0 win at Real Madrid on Saturday, their first success against their bitter city rivals in La Liga this century, Atletico recovered from conceding a 16th-minute Jackson Martinez goal at the Dragao stadium to secure a ninth victory in 11 matches in all competitions this term.

Their only blemish was a reverse on away goals to Barcelona in the two-legged Spanish Super Cup and they top the La Liga table alongside the champions with a perfect 21 points from seven matches.

Atletico's progress under coach Diego Simeone has been spectacular since the Argentine took over at the end of 2011 and he has moulded his squad into an outfit that looks capable of challenging the Barca-Real duopoly in Spain and progressing to the latter stages of Europe's elite club competition.

A combative and passionately committed midfielder for his country and during stints at Atletico, Sevilla, Inter Milan and Lazio, Simeone has instilled the same qualities in his players and praised their grit in Tuesday's post-match news conference.

Their success against the Portuguese side was all the more remarkable given that forward and top scorer Diego Costa was suspended and that they sold prolific Colombia striker Radamel Falcao to Monaco in the close season.

"We have an extraordinary group," Simeone said. "I am no doctor but the players were wounded and tired and that is a source of satisfaction as it shows they gave their all."

Atletico's Uruguay centre back Diego Godin headed the equaliser in the 58th minute before a well-worked free kick routine set up Turkey playmaker Arda Turan to snatch the winner four minutes from time.

The Spanish side top the group with six points from two games, with Porto on four in second and Zenit St Petersburg and Austria Wien, who drew 0-0 in Russia on Tuesday, on one point each in third and fourth respectively.

"We are just taking each match at a time," Godin told reporters.

"We are fighting to the death in every game and I think that is the right path to follow," he added. "Then we'll see how far that takes us."

Atletico's next outing is a La Liga clash at home to Celta Vigo on Sunday before away and home matches against Austria Wien on Oct. 22 and Nov. 6 respectively. (Editing by John O'Brien)