PORTO ALEGRE, Nov 8 (Reuters) - Title challengers Internacional missed a chance to open up a gap at the top of Brazil’s Serie A on Sunday when they were held to a 2-2 draw at home by Coritiba.Inter had not won in the league since Oct. 18 but Yuri Alberto put them in front after 33 minutes with a powerful header only for Giovanni Augusto to equalise three minutes after the break.Inter had Heitor Rodrigues da Fonseca sent off after 55 minutes but they still managed to take the lead again when Nonato completed a counter attack on the hour.Coritiba, however, pegged them back once more with a Sabino header 16 minutes from fulltime.The result leaves Inter one point ahead of reigning champions Flamengo, who play away at fourth-placed Atletico Mineiro later on Sunday.(Reporting by Andrew Downie Editing by Toby Davis)