Celtic manager Gordon Strachan has warned his players they need to up their game to clinch their third Scottish Premier League title in a row. The Parkhead side lost to Inverness Caledonian Thistle and drew with Hibernian, St Mirren and Hearts in December.

The run has dented their hopes of retaining the crown. Although Celtic still top the SPL table, second-placed Rangers are only two points behind having played two games less.

Celtic did manage to beat bottom-of-the-table Gretna 3-0 on Saturday, but Strachan is worried his side's stuttering recent form could see them lose their grip on the trophy. "We didn't use the ball as well as we could against Gretna and had too many touches on the ball," he said.

"Rangers have been the most consistent side so far in terms of points collected per game and are doing very well. So it's important that we win our games now as we need to stay close to Rangers.

"They have been the most consistent side in the league the first half of the season and we aim to be the most consistent side in the second half. If we can do that then that will make it a good title race."

Celtic's games at home to Rangers on Wednesday and away to Motherwell on Sunday were both postponed as a mark of respect to the latter's skipper and former Bhoys star Phil O'Donnell, who died from heart failure after collapsing near the end of his side's 5-3 victory at home to Dundee United on Saturday. Motherwell's match away to Hibernian on Wednesday and Gretna's meeting at home to St Mirren were also called off.

Three other games did go ahead on Wednesday, with Dundee United defeating Hearts 4-1, Aberdeen beating Inverness Caledonian Thistle 1-0 at home courtesy of a Barry Nicholson penalty, and Falkirk winning 1-0 at Kilmarnock thanks to Carl Finnigan's early header. All three matches held a minute's applause and players wore black arm bands in memory of O'Donnell.

Transfer targets
Celtic's next game is now at home to Stirling Albion in the Scottish Cup on Saturday 12 January, and they could have a number of new signings in place by then. The Parkhead club have been linked with moves for several players, including Dundee United captain Barry Robson, Hibernian left-back David Murphy, Sevilla's German international defender Andreas Hinkel and Everton's James McFadden.

Strachan admitted he is hoping to improve his squad in January but would not be drawn on individual signing targets. "We're looking at several options," he revealed.

"At the moment we're getting on well with some targets and if they come off we'll have a stronger squad. But things can break down at the last minute so we'll just have to wait and see this month."

On Wednesday Robson proved why he has been linked with a move to Celtic by scoring a hat-trick as the Tannadice team eased aside Hearts 4-1. Noel Hunt grabbed United's other goal, with Christophe Berra ensuring the game was level at the break for Hearts, who ended the game with only eight players after the sending-offs of Lithuanian Marius Zaliukas, Lee Wallace and Michael Stewart.

Although United manager Craig Levein made it clear he is still hoping to hold on to Robson he admitted every player has their price. "We've not received any bids for Barry Robson and we don't want to sell him," he said.

"If he is going to leave then it will have to be on the club's terms and we need to get what is the true market value for him. If he keeps playing like he did against Hearts then his value will shoot up."