Dundee United are still in the race for the Champions League. United cut the gap to third-placed Motherwell to three points this weekend with a 2-0 win over St Johnstone but defender Sean Dillon anticipates further twists and turns before European places are decided. There are four games left and, with Rangers excluded as a result of their administration, third is the target to follow Celtic into Europe's premier club competition. Dillon said: "If you have a chance, you might as well have a go. We know it's going to be tough next week against Hearts, then playing the Old Firm twice in the space of a few days before going to Motherwell. There's a lot to do, but the first one is done. There's four big games to go. We just need to keep the heads right and make sure we're ready for Hearts." Hearts are now seven points behind front runner Motherwell after losing 3-0 to Rangers and may take their eye off the ball a little with the prospect of the William Hill Scottish Cup final against Hibs on 19 May. However, Dillon, a cup winner with United in 2010, does not believe Hearts will ease up on any front. He said: "We had the same kind of situation a couple of years' ago and we wanted to make sure we finished the league season well. It's not all about the cup. It is a massive game, but they'll be wanting to put on a show for their fans. We know it's going to be a tough game, but we've put ourselves in a good situation." Dillon is set to have a new central defensive partner against Hearts after Gavin Gunning suffered a suspected dislocated shoulder at McDiarmid Park. Manager Peter Houston is reluctant to put top scorer Jon Daly in defence, although the captain can play there, and is more likely to switch Robbie Neilson in from his right-back position.Dillon was involved in one of the game's pivotal moments as ex-United striker Francisco Sandaza was sent off for kicking out at him. Saints top scorer is out of contract at the end of the season now faces a minimum two-game ban for violent conduct. Dillon added: "I get on well with Fran, certainly no problems. The referee saw enough to do something about it. These things happen." Sandaza's suspension offers an opportunity to Derek Riordan, who made his Saints debut against United following a catalogue of suspensions and injuries. November saw Riordan return from a spell in China and asked to return to training with Hibs. The Easter Road had to turn down the request as they had other issues to deal with at the time with Colin Calderwood replaced by Pat Fenlon as manager. Riordan was offered training facilities at Kilmarnock and Perth and a short-term deal was agreed last month. Riordan has not thought beyond the SPL season, but is keen to travel to Hampden next month to watch Hibs, the team he supports and has played for in two spells, in the Scottish Cup final. Riordan said: "I've enjoyed it here. I'm just happy to play here until the end of the season. I just want to get some games in. Hopefully I'll get some tickets (for the final). If not I'll be devastated."