Mark Hughes hailed the performance of Micah Richards following the Manchester City defender's match-winning header against 10-man Sunderland.Richards has struggled badly at times over the past 18 months, during which he has lost his place in the England squad.But, now switched back to his favoured full-back berth, Richards revelled in the extra space on offer in Sunday's Premier League clash at Eastlands once George McCartney had been red-carded for hauling back Shaun Wright-Phillips and capped a fine display by nodding home Elano's curling free-kick 12 minutes into the second period."Micah will get some headlines today because of the goal but there was a real determination in his play generally," said Hughes after his side's 1-0 win."He made a positive impact in the opposition half."People forget he is only 20. Players have fluctuations in form at such a young age but he seems to be coming good at the business end of the season."The same cannot be said of Robinho, who endured another difficult afternoon.At £32.5million, the Brazilian cost City a British record transfer fee on the last day of the August transfer window and until the New Year looked well worth the investment.But he has now gone 13 games without a goal, missing a penalty just two minutes after McCartney was dismissed, the dismal effort saved by Marton Fulop."Robinho was confident enough to take the ball and try to score," said Hughes, defending his player against assessments that he is lacking in confidence."He wants to make a positive impact and he was disappointed not to put that one away."There were a few opportunities in the second half as well. The desire was there for everyone to see but he can't quite get that crucial goal."With the injury that forced Richards off apparently nothing more than a touch of cramp and Craig Bellamy introduced for half an hour as replacement for Valeri Bojinov, who came through his first start since August 2007, Hughes should be choosing from strength as his team step up their bid for a top-seven finish after the international break.