Sunderland kept up the pressure on Wigan with a thumping win over Plymouth thanks to a three-goal first-half haul.
Dean Whitehead put the Black Cats ahead with a header from Stephen Wright's cross and Whitehead turned provider to set up Julio Arca to fire in a second.
Marcus Stewart hit the third from the spot after Graham Coughlan fouled him.
Stephen Caldwell headed in a cross from Liam Lawrence, Plymouth got one back with Scott Taylor's low finish before Sean Thornton's strike wrapped it up.
Sunderland boss Mick McCarthy:
"It was tight for half an hour but we are going to get more tight games and more tense as teams make it difficult for us to play.
"We were very patient and, once we got the first goal, we finished comfortable winners and deservedly so.
"We are as consistent as Wigan and Ipswich, but at this stage is about who is mentally tougher."
Plymouth boss Bobby Williamson:
"We conceded two bad goals and the third one, the penalty, capped off the first half.
"The referee said it wasn't a penalty and I don't think it's right that his assistant made the decision, then we conceded another two bad goals.
"I want to thank the fans who made the long journey but I'm disappointed that we have let them down."
Sunderland: Myhre, Wright, Breen, Caldwell, McCartney, Whitehead (Thornton 45), Whitley (Lawrence 45), Robinson, Arca, Elliott, Stewart (Brown 79).
Subs Not Used: Ingham, Bridges.
Booked: Whitley, Elliott, Breen, Robinson.
Goals: Whitehead 31, Arca 40, Stewart 45 pen, Caldwell 75, Thornton 90.
Plymouth: McCormick, Connolly, Coughlan, Aljofree, Gilbert, Norris, Wotton, Gudjonsson (Evans 79), Capaldi, Chadwick, Blackstock (Taylor 79).
Subs Not Used: Worrell, Lasley, Doumbe.
Booked: Norris.
Goals: Taylor 88.
Att: 25,258.
Ref: M Cowburn (Lancashire).