Birmingham stretched their unbeaten away record in the Championship to four matches with a gritty 0-0 draw with Reading at the Madejski Stadium.Reading, now undefeated in five matches, had the better of the openings, with Danny Williams seeing a powerful effort clawed away by Birmingham's replacement goalkeeper Adam Legzdins in the first half.Birmingham spent much of the much on the back foot, with Lukas Jutkiewicz facing a mostly lone and unsuccessful battle up front.Birmingham went into the match in fourth place after successive wins over Norwich and Fulham, the latter 1-0 at Craven Cottage on Saturday.Clayton Donaldson netted the winner from a penalty, though he had missed an earlier spot-kick, to take his tally to three goals in two games. However, he started on the bench at the Madejski Stadium.Reading defeated Ipswich 2-1 at home last Friday thanks to a 95th-minute penalty from Williams.They were unbeaten in four league and EFL Cup matches.Unusually, both sides had to change their line-ups shortly before kick off due to injuries suffered in the warm-ups.Reading lost midfielder Joey van den Berg, who was replaced by George Evans, and Birmingham had to replace keeper Tomasz Kuszczak with Legzdins.Birmingham were first to threaten when Steve Cotterill's angled free-kick evaded a mass of bodies in the home area and struck keeper Ali Al Habsi, who knew little about it.Following an error from Williams, Maikel Kieftenbeld bore down on goal only to blaze his shot high and wide.Reading responded when Roy Beerens escaped along the right flank, but, from his deep cross, Stephen Quinn miscued an ambitious volley.Half-chances came and went for Birmingham, with Jutkiewicz and Che Adams failing to trouble Al Habsi.But they were grateful to Legzdins for making a fine save to keep out a fierce 25-yard drive from Williams.Legzdins had no problems saving a weak header from Yann Kermorgant from a Garath McCleary cross, while Jutkiewicz forced a decent near-post stop from Al Habsi at the other end.Birmingham dictated matters at the start of the second half, with Kieftenbeld and Robert Tesche dominating the midfield exchanges.Al Habsi fumbled a close-range effort from Jutkiewicz, with David Davis blasting the follow-up high over the crossbar.Reading responded with a period of pressure themselves as Williams saw a shot blocked and Paul McShane mistimed a free header from a McCleary corner.Defender Liam Moore also had a header blocked near the goal-line from a McCleary cross.As the game became spread Birmingham broke away, only for Jutkiewicz to nod weakly at Al Habsi from a Cotterill cross.But the defences won the day in a scrappy affair.