Better than expected half-year results at arms supplier BAE Systems pushed it into third place.
Troubled airline caterer Gate Gourmet languished at bottom spot after 700 workers volunteered to take redundancy. The news also helped to drag its customer, British Airways, into the table's bottom five.
BA was also hammered for raising its fuel surcharge on long-haul tickets to £60 amid soaring oil prices.
But PartyGaming, which topped the Monitor at the beginning of July took the table's second-worst spot. Shares in the online gambling firm, which enters the FTSE 100 this month, fell 33 per cent last week.
Office of Fair Trading criticism of MasterCard's 'unduly high' charges to retailers processing card payments helped put the firm in the third-worst position.
British Gas did only a little better in fifth from bottom when it announced its third major price rise in less than two years.
Reputation Monitor is compiled from Thomson Intermedia's National News Index, a measure of media sentiment that excludes stock market reports and passing mentions.
REPUTATION MONITOR - 6-12 September 2005 Ranking Rank last week Organisation NNI Best performers 1 1 Tesco 155.5 2 n/a E.ON 148.2 3 30 BAE Systems 147 4 2 Asda 129.1 5 67 Scottish Power 122.1 Worst performers* 1 1 Gate Gourmet -122.5 2 1,464 PartyGaming -101.6 3 1,438 Mastercard -73.6 4 1,396 British Airways -52.8 5 1,400 British Gas -48.3 Source: www.newsmetrics.co.uk/Thomson Intermedia plc *Rank last week is position from bottom of table.