Rangers earned the right to host Celtic in the fourth round of the Scottish Cup as goals from Jermain Defoe and Nathan Patterson either side of Kemar Roofe's double saw them easily sidestep Paul Hartley's Cove Rangers.

Here the PA news agency takes a look at what we learned from the weekend's action.

No sign of complacency as Rangers keep double dream on track

Steven Gerrard saw his side blow their chance to land the first domestic trophy of the season back in December when St Mirren because the only Scottish side this season to manage a victory over his side. The Ibrox boss rang the changes that night in Paisley as the Buddies chalked up a surprise win. This time Gerrard was able to rest his top stars and avoid a slip-up as a line-up containing seven changes to the team who drew with Celtic a fortnight ago cruised to a 4-0 win over Cove Rangers – setting up another crack at the Hoops in the last 16.

James Forrest is back and on the Scotland trail

The 29-year-old winger required ankle surgery following a Europa League tie against Riga last September. After a couple of recent appearances off the bench he started for the first time since then against League One side Falkirk at Parkhead on Saturday. Forrest looked fit and sharp and broke the deadlock with a deflected drive after the break, with the holders going on to win 3-0. Capped 35 times, he hopes to force his way back into Steve Clarke's squad for this summer's Euros.

No easy task for Glass to polish up shot-shy Dons

Aberdeen sneaked through against League One part-timers Dumbarton after Callum Hendry fired just their second goal in the last 11 games to clinch a 1-0 win. New boss Stephen Glass was forced to watch the game from quarantine after returning from the United States. The former Atlanta United coach – who is due to take over following next week's trip to St Johnstone – has brought in former England striking coach Allan Russell to join his backroom staff but they will have their work cut out sharpening up their new side's misfiring frontline after the Dons missed a truckload of chances to wrap up the win.

St Johnstone have a clean sheet habit

Zander Clark's penalty save from Charlie Adam helped Saints to a 1-0 win at Dundee, their fourth such win in five matches and a fifth clean sheet in six games. The Perth side are proving very hard to beat and Guy Melamed has given them a new threat up front and scored the winner at Dens Park. They are on collision course with Celtic or Rangers in the quarter-finals but neither of the big two would have an easy time of it against Callum Davidson's men.

Red-hot Kyle Lafferty heating up at perfect time for Killie

Tommy Wright was looking for someone to spearhead the Rugby Park revival when he took over and in his fellow Northern Irishman Kyle Lafferty he looks to have found it. The former Rangers and Hearts ace has struck five goals in six appearances since signing. The 33-year-old's latest haul was a hat-trick against Stenhousemuir – his first treble since firing Gers to the title against Killie at Rugby Park on the final day of the 2010-11 season. Wright will hope he can keep it going when his second-bottom outfit return to league action Ross County on Saturday.