Frank Lampard has already staved off two potential indignities of late. Unlike Gary Lineker, he has avoided having to dress up as a sandwich, his face peering out between plastic tranches of ham and foam tomatoes, when filming the latest Walkers Crisps advertisement in Kent. Then, in a kickabout at Sandwich Technology school, his five-a-side team have edged out a comically dismayed Lineker's in a penalty shoot-out. Yet, if that provides some light relief, swerving the biggest ignominy of all could be distinctly trickier.

Chelsea confront Internazionale on Tuesday with a first-leg deficit to retrieve and Lampard's mentor, José Mourinho, blocking passage to the Champions League quarter-finals. This afternoon's visit of his former club, West Ham, must feel like a distraction with the main event to come. The England midfielder will have had almost three weeks to stew over that 2-1 defeat in San Siro: time to curse the non-award of a penalty for a trip on Salomon Kalou, or the profligacy that has marginally tilted this tie towards the Italian champions. Time, too, to wonder what the Special One may concoct for the return. "It plays on your mind but we have to tell ourselves the tie's in the balance," Lampard says. "The frustration is we should never have lost that first game, but now we have to be careful. Inter have good players and a very clever manager who'll come with a plan. But to go out to José? Yeah, I guess you could call that unthinkable."

That admission is natural, yet prompts immediate reflection. "You know what? I try and take all that emotion out of it. I've got more respect for José Mourinho than for any other manager I've worked with because of what he did for me. I want to win the game, but it's not like I want to get one over on him. I just want to go through to the last eight. If you'd asked me at the start of the season who I'd want to win the European Cup if it wasn't going to be us, I'd have been happy to see José win it. He was great for me and I'm still close to him."

Mourinho was staggering for Chelsea. The Portuguese will be granted a tumultuous reception on Tuesday for what will be his second return to the ground where his name was once bellowed as he plundered two Premier League titles, two Carling Cups and an FA Cup in little more than three seasons. He will be welcomed as a returning hero with affection extended by those his team directly oppose. Chelsea have signed nine senior players since his departure in September 2007, of whom only Nicolas Anelka and Branislav Ivanovic are established first-team regulars. It may be awkward for the managers who have come and gone since to acknowledge, but the core of this squad remains Mourinho's.

One of its key performers is in his debt. The impact Mourinho had on Lampard is measured in more than mere winners' medals. It says everything that the 31-year-old, by his own admission, considered joining him in Milan at the beginning of last season before opting at the last to extend his contract at Stamford Bridge. "He gave me self-belief," the midfielder says. "He carried that aura around with him. It's very obvious that he believes in himself as a manager, and as a man, but he had this way of transmitting that confidence to his players. He just tried to make me believe in the player I could be, and helped me get to where I wanted to be. It was sad losing someone like that who you respect, but what he gave me stays with me. I'm a better player and a better person for having worked with him.

"The reason he's been a successful manager everywhere he's been is because of the atmosphere he creates in the dressing room by getting close to his players, working with them, respecting them. All of us who worked with him had that. He creates a real spirit, a family atmosphere, and he gets that extra 10% out of his teams by doing that. That's why you'll find the players who worked with him will talk about the times he was with us with such fondness.

"We didn't get any of his 'mind games' before or after the first leg. I met him in the tunnel before kick-off, then he said a quick hello to most of the lads as he walked past our coach after the game – he was in pretty good spirits, as you'd expect. He'll talk ahead of the second game with one eye on the match, and say what he wants to say, but he won't make it personal. There's too much respect there for that."

The Portuguese and Inter represent a daunting obstacle blocking Chelsea's pursuit of a treble. The league leadership can be regained from Manchester United this afternoon, while Aston Villa await in the FA Cup semi-finals. Securing the European Cup, the trophy that eluded Mourinho's Chelsea, has long been Roman Abramovich's objective. "What happened to us last season against Barcelona in the semis – knowing we should have beaten the best team in Europe only, for one reason or another, to go out – still hurts," says Lampard, suppressing a shudder at the memory of Tom Henning Ovrebo's judgment and Andrés Iniesta's stoppage-time equaliser. "Another year passes and you haven't won it, and it hurts more and more. We know this squad isn't going to go on forever. The closer you get to tasting that success, the more bitter it is when you miss out.

"But that's why the club brought Carlo Ancelotti in last summer, because of the fantastic experience he brings with him, particularly in this competition. He's proven in Europe after what he achieved with Milan. The year they beat Manchester United in the semi-final and Liverpool in the final [2007] they had a fantastic team. He brings that know-how to us. He knows what is needed, particularly in the knock-out phase. That's why the game against Inter will be as much of a battle between two great managers as it is two teams. In Ancelotti, we've got a manager who can help us take that extra step.

"Everything that's happened this season must have been an eye opener for him: when you've played and coached all your career in Italy, coming to England must highlight the cultural differences in the game. That goes for the football and the style of play, the atmosphere, to the press – in Italy there's probably more attention paid to the football itself, whereas here there's also the off-the-field stuff which he wouldn't have encountered before. But he's done well. The frustrating thing is, as a group, we haven't been able to pull away at the top of the Premier League. That's down to the players. There have been times when we thought we'd push on, but then gone out and lost points."

Chelsea have not been alone in stuttering when they had expected to stride on. January was littered with wins, but there were only two victories last month together with that first-leg defeat in Italy. Key players have been lost to injury and Gianfranco Zola's West Ham may sense vulnerability across the capital. Concede today and Chelsea will have already shipped more goals this season than in any campaign since 2003-04. "But now's the time to put that consistent run of wins together," Lampard says. "There are three teams in it, but big teams put together a run in this situation. From now on in, we have to have that strong mentality to handle other sides playing before us and knocking us off the top of the league. We have to get our heads round that and go on a run of wins. But we've got the players to cope with that.

"For the last three seasons we've lost the league for different reasons. Last season we had a terrible patch at the end of [Luiz Felipe] Scolari's reign but, when Guus Hiddink came in, we were probably the best team in the country and lost once in four months. We did the same under Avram Grant, starting virtually in mid-table but almost nicking the league. That's the consistency we'll need. You learn from those close failures. We know what went wrong back then, and we have to copy what went right. The treble is still there for us.

"These could be a special five months. At Chelsea we have great potential and we're fighting on all fronts. We want to win big things – the Champions League in particular – and then, come June, there's the World Cup, the biggest tournament a player can participate in. World Cups define careers. We'll go to South Africa full of confidence. All this is exciting, mouth-watering, but one thing at a time. First West Ham, then Inter." A reunion with Mourinho awaits.

Frank Lampard stars in the new Walkers Sandwich campaign. Visit www.walkers.co.uk